A compact demodulation reference is disclosed for compatibility with reduced-capability user devices, and for enhanced throughput for high-performance user devices of 5G and 6G in high-density environments. The demodulation reference, in some embodiments, occupies only one resource element, yet provides sufficient information to enable a receiver to calculate all of the amplitude or phase modulation levels of the modulation scheme. For example, if the modulation scheme is 16QAM, the demodulation reference can include an I branch with the highest amplitude level of the modulation scheme and an orthogonal Q branch with the lowest amplitude level. Further examples apply to a multiplexed amplitude-phase modulation scheme. In each case, the receiver can calculate the remaining amplitude (or phase) modulation levels, and thereby demodulate a proximate message. Further examples show how to reveal faulted message elements by comparing demodulation with QAM and amplitude-phase demodulation, and how to optimize noise margins.

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 of recovering information encoded by a modulated sinusoidal waveform having first, second, third and fourth data notches at respective phase angles, where a power of the modulated sinusoidal waveform is reduced relative to a power of an unmodulated sinusoidal waveform within selected ones of the first, second, third and fourth data notches so as to encode input digital data. The method includes receiving the modulated sinusoidal waveform and generating digital values representing the modulated sinusoidal waveform. A digital representation of the unmodulated sinusoidal waveform is subtracted from the digital values in order to generate a received digital data sequence, which includes digital data notch values representative of the amplitude of the modulated sinusoidal waveform within the first, second, third and fourth data notches. The input digital data is then estimated based upon the digital data notch values.

A data transmission system includes a transmitter circuit. The transmitter circuit receives regular data bits and auxiliary data bits. The transmitter circuit encodes a first subset of the regular data bits to generate a first subset of encoded data comprising pairs of symbols that are used in quadrature amplitude modulation. The transmitter circuit encodes the auxiliary data bits and a second subset of the regular data bits to generate a second subset of the encoded data comprising at least one pair of symbols that are unused for encoding by the quadrature amplitude modulation. The transmitter circuit generates a modulated output signal that indicates the first and second subsets of the encoded data using pulse amplitude modulation.

In some implementations, a device may provide content received via a quadrature amplitude modulation channel. The device may receive supplemental content information regarding supplemental content to be provided during a period of time associated with providing the content, wherein the supplemental content information includes a uniform resource locator (URL) identifying a location of the supplemental content and start time information identifying a time when the supplemental content is to be provided. The device may obtain the supplemental content using the URL. The device may transition, from providing the content, to providing the supplemental content based on the start time information. The device may transition, from providing the supplemental content, to providing the content after providing the supplemental content.

Short-form pulse-amplitude demodulation references disclosed herein may enable low-cost receivers to demodulate wireless messages while avoiding complex 5G and 6G protocols, thereby enabling a multitude of cost-constrained applications. Despite their small footprint, the short-form pulse-amplitude demodulation references enable the receiver to determine all of the amplitude levels of the modulation scheme, including the effects of noise and interference. Mitigation of noise and interference can therefore be provided by embedding short-form pulse-amplitude demodulation references within longer messages, thereby providing an immediate refresh of the modulation calibrations, enhancing communication reliability, and avoiding costly message faults despite high background interference. Short-form pulse-amplitude demodulation references disclosed herein can be used as a default standard demodulation reference in 5G and 6G wireless messages.

A transmitter for transmitting payload data and emergency information using data symbols in a single-carrier or multi-carrier broadcast system comprises a modulator configured to modulate one or more transmission symbols with signaling data for use in detecting and recovering the payload data at a receiver and to modulate one or more transmission symbols with the payload data. An emergency information receiver receives emergency information carrying information of an actual emergency. An emergency information embedder embeds emergency information into one or more transmission symbols, wherein the emergency information is embedded within a predetermined time period after its reception by using a resource used for carrying signaling data and/or payload data if no emergency information shall be transmitted. A transmission unit transmits the transmission symbols.

An optical transmitter device (14) includes a digital signal processor ‘DSP’ (20) having digital hardware (30). The DSP is operative to generate (102,202,302) shaped bits from a first set of information bits, and to apply (104,204,304) a systematic forward error correction ‘FEC’ scheme to encode the shaped bits and a second set of information bits, where the first set of information bits and the second set of information bits are disjoint sets. Unshaped bits and the shaped bits are mapped to selected symbols or are used to select symbols from one or more constellations. The selected symbols are mapped to physical dimensions. Each unshaped bit is either one of the second set of information bits or one of multiple parity bits resulting from the FEC encoding. In this manner, a target spectral efficiency is achieved.

In a transmitter apparatus, a known reference signal is superimposed on top of a data signal that is typically not known a priori to a receiver and the combined signal is transmitted. At a receiver, an iterative channel estimation and equalization technique is used to recover the reference signal and the unknown data signal. In the initial iteration, the known reference signal is recovered by treating the data signal as noise. Subsequent iterations are used to improve estimation of received reference signal and the unknown data signal.

Provided are systems and methods for transmitting data over a wireless channel from a data transmitting node to a data receiving node in a communication system. The data transmitting node comprises second-layer processing circuitry for receiving at least one second-layer SDU, to be mapped onto a resource allocated for data transmission, and for generating a second-layer PDU, including the at least one second-layer SDU and at least one second-layer control element, and first-layer processing circuitry for receiving the second-layer PDU generated by the second-layer processing circuitry and for mapping the second-layer PDU onto the resource allocated for data transmission. The data receiving node comprises first-layer processing circuitry for de-mapping at least one second-layer PDU, and second layer processing circuitry for receiving and parsing the second-layer PDU demapped by the first-layer processing circuitry, the second-layer PDU including at least one second-layer SDU, and at least one second-layer control element.