Disclosed are short-form demodulation reference signals configured to indicate certain modulation levels of a modulation scheme, from which a receiver can measure phase noise and amplitude noise in 5G/6G. A key feature of short-form demodulation references is resource efficiency. Examples include a demodulation reference occupying just one resource element, while providing the information needed to determine all of the modulation states of the modulation scheme, as well as the current noise factors. In one embodiment, the short-form demodulation reference may include two component signals with orthogonal phase, both being amplitude modulated by the transmitter according to a maximum amplitude level. The receiver can determine the phase noise from a ratio of the two received signal amplitudes, and the amplitude noise from the magnitude of the received waveform, thereby mitigating both amplitude noise and phase noise. The short-form demodulation reference can be added to each message for real-time noise mitigation.

A method implemented by a Wireless Transmit/Receive Unit (WTRU) includes receiving a DeModulation Interference Measurement (DM-IM) resource, determining an interference measurement based on the DM-IM resource, and demodulating a received signal based on the interference measurement. An interference is suppressed based on the interference measurement. At least one DM-IM resource is located in a Physical Resource Block (PRB). The DM-IM resource is located in a PRB allocated for the WTRU. The DM-IM resource is a plurality of DM-IM resources which form a DM-IM pattern, and the DM-IM pattern is located on a Physical Downlink Shared Channel (PDSCH) and/or an enhanced Physical Downlink Shared Channel (E-PDSCH) of at least one Long Term Evolution (LTE) subframe. The DM-IM resources are different for different Physical Resource Blocks (PRB) in the LTE subframe. The DM-IM is located in a Long Term Evolution (LTE) Resource Block (RB), and the DM-IM pattern is adjusted.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a transmitter, a reference signal block provided based at least in part on an orthogonal frequency division multiplexing (OFDM) waveform. The UE may perform an estimation operation based at least in part on the reference signal block. The UE may receive a data transmission via a single carrier waveform based at least in part on the estimation operation. Numerous other aspects are provided.

A signal specification identification apparatus includes processing circuitry that estimates the transmission rate of a received signal, performs sampling frequency conversion on the received signal, calculates a probability corresponding to each of a plurality of candidates for a specification of the received signal, selects a candidate using the respective probabilities, and calculates reliability corresponding to a selected candidate, determines whether to output the selected candidate as an identification result or perform the sampling frequency conversion again, based on the reliability, and changes a parameter indicating the ratio of the sampling frequency conversion when it is determined that the sampling frequency conversion is to be performed again. Processing is repeated until the processing circuitry determines that the selected candidate as the identification result is to be output.

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.

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.

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.

A method of reducing transmission power for an encoded data stream includes the steps of receiving an incoming data stream having equal probability for a plurality of incoming data bits, assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits, and transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols.

The present invention discloses a data transmission method and apparatus, and a user equipment. The method includes: classifying, by using a transmission time interval TTI as a classification basis, TTIs on a carrier in a cell into a time division multiplexing TDM TTI and a code division multiplexing CDM TTI; and sending, to a user equipment UE, control information carrying a classified result, so as to instruct the UE to send uplink data according to the classified result and a data scheduling type of the UE in the TDM TTI or the CDM. By using the foregoing technical solution, a data transmission resource can be well saved and scheduling flexibility can be improved.

Systems, devices, and methods of the present invention facilitate secure communication by changing sets of symbol waveforms used transmit data in particular symbol times defined herein as Symbol Waveform Hopping. SWH may be enabled by selecting two or more modulation formats that have sufficiently comparable communication performance (e.g., occupied bandwidth and signal power efficiency) to enable successful sending of data between a transmitter and receiver employing SWH, but characterized by symbol waveform alphabet that include different symbol waveform, so that the overall transmission/communication performance of data stream in a signal transmission channel of the system is not significantly affected by switching between modulation formats, but one symbol waveform alphabet is not reliably able to receive signals sent using the other alphabets. Some or all of the symbol waveforms in each alphabet may not be present in other alphabets.