Abstract: Systems, devices, and methods are described for multi-band spread spectrum communication. A communication system, which may include any number of communication nodes, may include a first communication node including a dedicated first number of subcarrier bands, and a second communication node including a dedicated second number of subcarrier bands. The first communication node may be configured to transmit a link request to the second communication node over the first number of subcarrier bands, and the second communication node may be configured to transmit another link request to the first communication node over the second number of subcarrier bands.

Abstract: A method of recovering transmitted symbols. The method receiving a signal comprising a codeword, the signal having been affected by channel effects including distortion and noise. A solution space for recovering the transmitted symbols is identified, including finding a sampling center using a full matrix W for minimum mean square error. A vector v? is generated to generate noise. The vector has a variance ??n2 where ?n2 is a factor that defines power of added noise and where ? is a scaling parameter that controls a size of a noise sampleable space. The vector v? is applied to the solution space. Original samples are gathered from the solution space, which includes noise from the vector v? and symbol information from the received signal to find probabilities for symbols. Using the probabilities, the symbols are recovered.

Abstract: Systems and methods for symbol detection. The methods comprising: receiving, by a receiver, a signal that was transmitted in a single carrier transmission system; detecting, by a processor of the receiver, a plurality of first symbols in the received signal that are to be detected and a plurality of second symbols in the received signal that are to be considered interfering symbols; cancelling, by the processor, interference from the received signal using the plurality of second symbols to obtain a modified received signal; obtaining, by the processor, soft values using a stochastic detection algorithm that considers each of the plurality of first symbols as being transmitted from respective virtual transmitters and received by respective virtual receivers; and using the soft values to recover symbols from the received signal.

Abstract: A method of recovering transmitted symbols. The method receiving a signal comprising a codeword, the signal having been affected by channel effects including distortion and noise. A solution space for recovering the transmitted symbols is identified, including finding a sampling center using a full matrix W for minimum mean square error. A vector v? is generated to generate noise. The vector has a predefined variance. The vector v? is applied to the solution space. Original samples are gathered from the solution space, which includes noise from the vector v? and symbol information from the received signal to find probabilities for symbols. Using the probabilities, the symbols are recovered.

Abstract: A method of recovering transmitted symbols. The method receiving a signal comprising a codeword, the signal having been affected by channel effects including distortion and noise. A solution space for recovering the transmitted symbols is identified, including finding a sampling center using a full matrix W for minimum mean square error. A vector v? is generated to generate noise. The vector has a variance ??n2 where ?n2 is a factor that defines power of added noise and where ? is a scaling parameter that controls a size of a noise sampleable space. The vector v? is applied to the solution space. Original samples are gathered from the solution space, which includes noise from the vector v? and symbol information from the received signal to find probabilities for symbols. Using the probabilities, the symbols are recovered.

Abstract: Various embodiments relate to spread spectrum communication. A communication system may include a base station and a user equipment. The base station may be configured to: add a cyclic prefix (CP) to each block of a number of blocks of a first direct sequence spread spectrum (DSSS) signal to generate a first cyclic prefix-direct sequence spread spectrum (CP-DSSS) signal; add artificial noise to the first CP-DSSS signal; and transmit, via a channel, the first CP-DSSS signal. The user equipment is configured to receive the first CP-DSSS signal. Associated methods and communications systems are also disclosed.

Abstract: Systems, devices, and methods are described for multi-band spread spectrum communication. A communication system, which may include any number of communication nodes, may include a first communication node including a dedicated first number of subcarrier bands, and a second communication node including a dedicated second number of subcarrier bands. The first communication node may be configured to transmit a link request to the second communication node over the first number of subcarrier bands, and the second communication node may be configured to transmit another link request to the first communication node over the second number of subcarrier bands.

Abstract: Various embodiments relate to spread spectrum modulation. A device may include a processor and at least one transmitter. The device may be configured to add a cyclic prefix (CP) to each block of a number of blocks of a direct sequence spread spectrum (DSSS) signal to generate a cyclic prefix-direct sequence spread spectrum (CP-DSSS) signal. Further, the device may be configured to transmit, via a channel, the CP-DSSS signal. Associated methods and communications systems are also disclosed.

Abstract: An unmanned aerial vehicle (UAV) and base station are disclosed that communicate within a first cell via schedule requests to set up transmission of up-link data. The UAV additionally communicates up-link data via a grant-free underlay broadcast channel to one or more neighboring base stations of the terrestrial cellular network. Transmitters, receivers, related methods are also disclosed for modulation and demodulation of the transmission packets.

Abstract: Apparatuses, systems, and methods are disclosed for stochastic linear detection. A digital signal processor determines information about a plurality of transmitted signals based on a plurality of received signals. An initialization module determines an estimator matrix and a noise shaping matrix based on channel state information that relates the transmitted signals to the received signals. A sample generation module stochastically generates a plurality of signal estimates so that each signal estimate is a sum of a fixed component and a random component. The fixed component may be based on applying the estimator matrix to a vector of the received signals, and the random component may be based on applying the noise shaping matrix to generated noise. An output module sends soft information to an error-correcting code (ECC) decoder for decoding bits carried by the transmitted signals. The soft information may be based on the plurality of signal estimates.

Abstract: Apparatuses, systems, and methods are disclosed for stochastic linear detection. A digital signal processor determines information about a plurality of transmitted signals based on a plurality of received signals. An initialization module determines an estimator matrix and a noise shaping matrix based on channel state information that relates the transmitted signals to the received signals. A sample generation module stochastically generates a plurality of signal estimates so that each signal estimate is a sum of a fixed component and a random component. The fixed component may be based on applying the estimator matrix to a vector of the received signals, and the random component may be based on applying the noise shaping matrix to generated noise. An output module sends soft information to an error-correcting code (ECC) decoder for decoding bits carried by the transmitted signals. The soft information may be based on the plurality of signal estimates.

Abstract: Circularly pulse-shaped waveforms for communication systems are disclosed herein, including a single carrier modulation in which pulse-shaping is performed using a circular convolution by the transmitter for various modulation schemes. A transmitter, related method, and corresponding receiver are also disclosed for demodulation of the single carrier circularly pulse-shaped signal and data extraction.

Abstract: A communication device, a method of operating a communication device, and a spread-spectrum receiver are disclosed. The method includes receiving an incoming RF signal, demodulating the incoming RF signal to generate a baseband signal, filtering the baseband signal with a normalized matched filter having filter characteristics matched to a pulse-shaping filter of the transmitter that generated the incoming RF signal, and extracting a received signal from a normalized output generated by the normalized matched filter. As a result, interferences and noise from harsh environments may be suppressed.

Abstract: A communication device, a method of operating a communication device, and a spread-spectrum receiver are disclosed. The method includes receiving an incoming RF signal, demodulating the incoming RF signal to generate a baseband signal, filtering the baseband signal with a normalized matched filter having filter characteristics matched to a pulse-shaping filter of the transmitter that generated the incoming RF signal, and extracting a received signal from a normalized output generated by the normalized matched filter. As a result, interferences and noise from harsh environments may be suppressed.

Abstract: An unmanned aerial vehicle (UAV) and base station are disclosed that communicate within a first cell via schedule requests to set up transmission of up-link data. The UAV additionally communicates up-link data via a grant-free underlay broadcast channel to one or more neighboring base stations of the terrestrial cellular network. Transmitters, receivers, related methods are also disclosed for modulation and demodulation of the transmission packets.

Abstract: Wireless communication systems, base stations, and user equipment are disclosed that enable communication of scheduling requests via an underlay control channel that has an energy below a noise level of the spectrum. The scheduling requests may be sent and received at any time, including during downlink and uplink data communication periods of the base station.

Abstract: Apparatuses, systems, and methods are disclosed for stochastic interference cancellation. A digital signal processor decodes a set of transmitted signals based on a set of received signals. A projection module updates a subset of a set of estimated signals based on error information and on a corresponding subset of mapping information. Error information is based on the received signals and the set of estimated signals. Mapping information indicates how the received signals are affected by the transmitted signals. A stochastic update module adjusts the set of estimated signals based on generated noise. An interference cancellation module updates the error information based on the adjusted estimated signals.

Abstract: Wireless communication systems, base stations, and user equipment are disclosed that enable communication of scheduling requests via an underlay control channel that has an energy below a noise level of the spectrum. The scheduling requests may be sent and received at any time, including during downlink and uplink data communication periods of the base station.

Abstract: Circularly pulse-shaped waveforms for communication systems are disclosed herein including a single carrier modulation in which pulse-shaping is performed using a circular convolution by the transmitter for various modulation schemes. A transmitter, related method, and corresponding receiver are also disclosed for demodulation of the single carrier circularly pulse-shaped signal and data extraction.

Abstract: A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.