Disclosed are methods for base stations to indicate the start and end of a downlink message, by prepending and appending demarcations to the message in 5G or 6G. A user device can then readily locate the message by detecting the demarcations, greatly reducing the amount of computation required of the receiver processor. There may be no need for a DCI message alerting the user device of the comming message. Each demarcation may be a brief predetermined bit sequence such as a demodulation reference or an identification code of the intended recipient. The start and end demarcations may be different, and may include a gap of zero or low transmission, to further assist the receiver. The user device may transmit a request message to the base station, requesting that demarcations be applied to the user's downlink messages, and declining the redundant DCI alert messages, thereby saving further energy and network overhead.

A method for automatically detecting a packet mode in a wireless communication system supporting a multiple transmission mode includes: acquiring at least one of data rate information, packet length information and channel bandwidth information from a transmitted frame; and determining the packet mode on the basis of the phase rotation check result of a symbol transmitted after a signal field signal and at least one of the data rate information, the packet length information and the channel bandwidth information acquired from the transmitted frame.

Apparatus and methods for identifying a wireless signal-emitting device are disclosed. The apparatus is configured to sense and measure wireless communication signals from signal-emitting devices in a spectrum. The apparatus is operable to automatically detect a signal of interest from the wireless signal-emitting device and create a signal profile of the signal of interest; compare the signal profile with stored device signal profiles for identification of the wireless signal-emitting device; and calculate signal degradation data for the signal of interest based on information associated with the signal of interest in a static database including noise figure parameters of a wireless signal-emitting device outputting the signal of interest. The signal profile of the signal of interest, profile comparison result, and signal degradation data are stored in the apparatus.

A Radio Frequency (RF) receiver may include a lower-order phase shift keying (PSK) demodulation circuit configured to generate at least one locking parameter when performing a lower-order PSK demodulation of an RF receive signal having an interfering PSK signal component. A higher-order PSK demodulation circuit has a higher order than the lower-order PSK demodulation circuit, and locks to the RF receive signal using the at least one locking parameter from the lower-order PSK demodulation circuit. The higher-order PSK demodulation circuit performs the higher-order PSK demodulation of the RF receive signal based upon locking to the RF receive signal to determine the interfering PSK signal component.

In the present invention, in classifying modulation types of a plurality of modulation signals by using a classifier (an artificial neural network model based on machine learning), the classifier may classify the modulation types of the modulation signals by using pieces of I/Q data, sampled with one sampling frequency, as input data, and thus, may quickly classify the modulation signals.

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.

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.

A method for estimating information symbols conveyed by a signal including modulated chirps. The modulation corresponds to circular permutation of the pattern of variation in the instantaneous frequency of a basic chirp over the symbol time. A first demodulation of a portion of the signal that is representative of at least two chirps delivering: an estimation of a first modulation symbol associated with a first chirp with a stronger amplitude among the two chirps, an estimation of the amplitude and phase of the first chirp, a generation of a signal that is representative of the first chirp from the estimation, and a coherent subtraction of the signal that is representative of the first chirp from the portion of the signal delivering an updated portion of the signal. A second demodulation of the updated portion delivering an estimation of a second modulation symbol associated with a second chirp.

A method, system and apparatus for audio communication modulation mode self-adaptation, and an electronic signature token are provided. The method includes generating a first audio detection frame; if the first audio detection frame is correct, selecting the modulation mode supported by the second device corresponding to the identifier of the modulation mode supported by the second device from pre-stored modulation modes supported by the second device according to the identifier of modulation mode supported by the second device carried in the first audio detection frame, and generating a first audio detection feedback frame; if the first audio detection feedback frame is correct, demodulating an audio data frame from the second device using a demodulation mode corresponding to the modulation mode supported by the second device, and demodulating an audio data frame from the first device using a demodulation mode corresponding to the modulation mode supported by the first device.

A correlating mixed signal spectrum analyzer receiver is provided that automatically correlates signals in a mixed-signal environment with a large number of waveforms having different characteristics corresponding to different protocols and modulation types, with the receiver utilizing either parallel correlators or sequential correlations to automatically accommodate the different waveforms such that in any given testing cycle, the spectrum analyzer runs through a comprehensive list of waveforms to detect the existence of corresponding signals. Frequency drift compensation and the utilization of multiple receivers for providing time difference of arrival calculations is described.