Methods and apparatus for preamble detection in a communication network are disclosed. In an exemplary embodiment, a method includes retrieving parameters from a parameter database, filling a buffer of preamble data received in an uplink transmission from user equipment, and frequency shifting the buffer of preamble data based on one or more first parameters to generate frequency shifted data. The method also includes oversampling the frequency shifted data to generates oversampled data, downsampling the over sampled data based on one or more second parameters to generate preamble samples, and updating the parameter database with updated values for the one or more first and second parameters. The method also includes repeating all the operations until a selected amount of preamble samples is obtained.

Aspects of the present disclosure include methods for communication using a MIMO channel, such as an acoustic channel for underwater communication. An acoustic receiver may receive a signal comprising information encoded in at least one transmitted symbol. Using a two-layer iterative process, the at least one transmitted symbol is estimated. The first layer of the two-layer process uses iterative exchanges of soft-decisions between an adaptive turbo equalizer and a MAP decoder. The second layer of the two-layer process uses a data-reuse procedure that adapts an equalizer vector of both a feedforward filter and a serial interference cancellation filter of the adaptive turbo equalizer using a posteriori soft decisions of the at least one transmitted symbol. After a plurality of iterations, a hard decision of the bits encoded on the at least one transmitted symbol is output from the MAP decoder.

Various embodiments provide for data transmission using modulated carrier signals to carry data, where the carrier signal comprises a predetermined sequence of symbols. An embodiment can be used in such applications as data network communications between sensors (e.g., cameras, motion, radar, etc.) and computing equipment within vehicles (e.g., smart and autonomous cars).

A converged radio unit (RU) configured for semantic-less retransmissions comprises a radio-frequency machine learning (RFML) radio unit (RFML RU) and a radio-access network (RAN) radio unit (RU). The RFML RU may be configured to receive an RF signal comprising a packet, decode a PHY layer preamble of the packet, and apply a machine-learning (ML) model to information obtained from only the PHY layer preamble to classify the packet. When the packet is classified be a tactical data link (TDL) packet based on the information obtained only from the PHY layer preamble, the RFML RU may retransmit the packet. When the packet is classified a RAN protocol packet, the RFML RU may be configured to signal the RAN RU to process the RAN protocol packet in accordance with a RAN protocol.

A data link (101) for a MIMO communication system (100) comprises a first transceiver device (106A) comprising a body (109A) having a transducer mounting surface near or at which is mounted a plurality of first transducers (107A-107D) configured to, in use, receive and convert a plurality of electrical waveforms to a respective plurality of acoustic signals. A first bonding layer (120A) bonds a barrier mounting surface of the body of the first transceiver device to a barrier (103). The data link further comprises a second transceiver device (106B) comprising a body (109B) and a plurality of second transducers (107′A-107′D) configured to receive and convert the plurality of acoustic signals transmitted through the barrier to a respective plurality of electrical waveforms. A second bonding layer (120B) bonds a barrier mounting surface of the body of the second transceiver to the barrier.

An IQ generator capable of consuming lower power and occupying smaller die area. The IQ generator is configured without any synthesizer and divide-by-2 circuitry. The IQ generator may be configured to convert one or more phase outputs of a test tone generator (TTG) into I and Q signals. The IQ generator may receive as inputs differential outputs of a single phase of a TTG and/or multiple phase outputs of a TTG. The IQ generator may include one or more delay paths configured to generate the I and Q signals, and a calibration circuitry configured to compare the average pulse widths of the I and Q signals and provide one or more control signals to the one or more delay paths such that the I and Q signals are orthogonal in phase.

Methods, systems, and devices for wireless communications are described. Pre-discrete Fourier transform (DFT) time-domain spreading codes may be applied for UE multiplexing for uplink control information (e.g., over shared resources of an uplink slot). For example, a moderate number of UEs may be multiplexed within the same slot by having each UE spread modulation symbols before DFT-spreading by different spreading code. For orthogonality across UEs, the pre-DFT spreading codes may be selected as orthogonal cover codes (OCCs). The spreading sequences can be generated from a set of any orthogonal sequences or generated from unitary matrices. In some cases, orthogonality in the time domain may be kept as well as a frequency division multiplexed (FDM) structure in the frequency domain. For such property, a Fourier basis OCC design may be used. In some other examples, a Hadamard matrix based OCC design may be used.

A wireless device may include: a radio frequency (RF) front end circuit to receive and process an RF signal; a mixer to downconvert the RF signal to a second frequency signal; a digitizer to digitize the second frequency signal; a channel filter to channel filter the digitized signal; a selection circuit having a first input coupled to the channel filter and a plurality of outputs each to couple to one of a plurality of demodulators; and the plurality of demodulators coupled to the selection circuit. The selection circuit may route the channel filtered digitized signal to a first demodulator of the plurality of demodulators based on a first configuration setting. The wireless device may also include a non-volatile storage with a configuration file including the first configuration setting. The configuration file may be automatically generated by a hardware configurator in response to a plurality of user input parameters.

The present disclosure relates to adaptive modulation and coding scheme selection and signaling in a communication system. In particular, a modulation and coding scheme to be used for transmission of a data is selected from a set of predetermined modulation and coding schemes. The predetermination of the set is performed by selecting the set from a plurality of predefined sets. The sets have the same size, so that a modulation and coding selection indicator signaled to select the modulation and coding scheme may be advantageously applied to any of the selected sets. Moreover, a second set includes schemes with a modulation not covered by the schemes of a first set, and which is of a higher order than any modulation in the first set.

A differential chaos shift keying communication method based on hybrid index, including: modulating a transmitted signal based on the hybrid index; and demodulating a received signal based on the hybrid index. The hybrid index is a hybrid index bit, which includes a carrier index bit and a carrier number index bit. This application also provides a system for implementing the differential chaos shift keying communication method, which includes a transmitter and a receiver.