173 results about "QAM" patented technology

The present invention discloses an unified multiple access (MA) based system for uplink transmission of data by multiple users. The system comprises an user interface integrated transmitter modules for transmitting the data from multiple user transmitters over waveforms through a cooperative unified data grid structure including grid points, said unified data grid structure including each user transmitter allocation of a few non-overlapping grid points for loading respective data bearing symbols, with zeros loaded onto unallocated grid points. The user transmitter is configured to transmit a sparsely loaded grid resembling to the unified two-dimensional data grid structure involving data-bearing Quadrature Amplitude Modulation (QAM), where a part of available grid points of the grid as allocated is loaded with QAM symbols and remaining grid points are loaded with zero symbols. A waveform modulator corresponding to user transmitter is also provided in the present system for waveform modulation of said sparsely loaded grid as per the waveforms enabling transmission for multi-antenna reception of the waveforms to a base station or an access point.

Provided are a communication method and a communication device, the method comprising: determining a transmission waveform of a signal, the transmission waveform being related to a threshold of a first parameter, the first parameter comprising: a modulation order and a roll-off factor, the transmission waveform is an orthogonal frequency division multiplexing QAM-DFTS-OFDM waveform of discrete Fourier transform spread spectrum of orthogonal amplitude modulation or an orthogonal frequency division multiplexing OQAM-DFTS-OFDM waveform of discrete Fourier transform spread spectrum of offset orthogonal amplitude modulation, and the roll-off factor is determined based on the transmission bandwidth and the number of symbols carried by the transmission waveform. And transmitting or acquiring the signal. In the method provided by the invention, the network equipment or the terminal equipment can determine the transmission waveform of the signal according to the set threshold value of the modulation order and the threshold value of the roll-off factor, so that the output power supporting higher power amplifiers can be obtained, and a larger signal coverage range can be obtained.

The invention discloses a multipath effect suppression method for 2.4 GHz radio frequency identification. The multipath effect suppression method comprises a transmitting end processing flow and a receiving end processing flow. A transmitting end carries out pulse code modulation on an analog signal to obtain a digital signal, blocks the digital signal after channel coding, and distributes the digital signal to subcarriers through quadrature amplitude modulation; and generating a time domain OFDM symbol through IFFT (Inverse Fast Fourier Transform), adding a cyclic prefix and a synchronization head, converting into an analog baseband signal, and performing up-conversion, filtering, amplification and radiation. The receiving end amplifies the signal, down-converts the signal to a baseband, filters the signal and converts the signal into a digital signal; the method comprises the following steps of: synchronizing header frame alignment, recovering a coding bit stream through FFT (Fast Fourier Transform) and QAM (Quadrature Amplitude Modulation) demodulation, carrying out CRC (Cyclic Redundancy Check) after decoding and merging, returning ACK (Acknowledgement Character) if According to the method, the multipath effect can be effectively inhibited, and the integrity of received data is improved.

This application provides a communication method, apparatus, and system, to increase a data transmission rate of a terminal device using a DFT-S-OFDM waveform when a single uplink CC is used in a CA scenario. The communication method, apparatus, and system may be applied to a 5G system, a future communication system such as a 6G system, and other fields. The method includes: sending first indication information to the terminal device when a first condition is satisfied, and receiving data from the terminal device by using the DFT-S-OFDM waveform and a first modulation scheme. The first condition includes: There is one component carrier used by the terminal device to perform uplink data transmission in the carrier aggregation CA scenario. The CA scenario includes that CA is configured for uplink and / or CA is configured for downlink. The first indication information indicates to use the DFT-S-OFDM waveform and the first modulation scheme to perform uplink transmission. The first modulation scheme includes 16 quadrature amplitude modulation QAM or 64 QAM.

The invention discloses a signal transmission method, a signal receiving method, a channel sending end and a channel receiving end, and belongs to the technical field of communication, and the signal transmission method comprises the steps: obtaining to-be-sent original data, and generating a bit encryption factor, a constellation encryption factor, a bit disturbance factor and a constellation disturbance factor; the method comprises the following steps: dividing original data to be sent into even number of data blocks according to a preset rule to construct a complete binary tree, and carrying out first traversal encryption and primary disturbance on the data blocks by utilizing a bit encryption factor; converting the data block subjected to primary perturbation into a parallel bit stream through serial-parallel conversion, performing QAM mapping on the parallel bit stream, and performing second traversal encryption and second perturbation according to a constellation perturbation factor; the parallel bit streams after secondary disturbance are converted into serial signals through a discrete Fresnel inverse transformation matrix and parallel-serial conversion; and performing up-conversion processing on the serial signal and transmitting the serial signal to a transmission channel. According to the invention, the problem of insufficient safety protection in practical application in the prior art is solved.

Systems and devices are provided for receiving or transmitting IQ data (e.g., suitable for passband quadrature amplitude modulation (QAM)) over a wireline using pairs of baseband pulse amplitude modulation (PAM-n) signals. Encoding circuitry may map data from an input bit stream to IQ data that includes an in-phase component and a quadrature-phase component. Modulator circuitry may determine an in-phase PAM-n signal based on the in-phase component and a quadrature-phase PAM-n signal based on the quadrature-phase component. Driver circuitry may transmit the in-phase PAM-n signal and the quadrature-phase PAM-n signal across a wireline channel. The in-phase PAM-n signal may be different by 90° from the quadrature-phase PAM-n signal. This may enable a remote receiver on the wireline channel to detect the in-phase PAM-n signal independently of the quadrature-phase PAM-n signal.

Aspects of the present application provide methods and devices for a phase tracking reference (PT-RS) scheme for use by a single carrier Offset QAM (SC-OQAM) transmitter and receiver to estimate, and correct, phase errors that occur over the communication link between the SC-OQAM transmitter and receiver. A transmitter may set the sign (positive or negative) of PT-RS symbols dynamically allowing the transmitter to better utilize IQ interference caused by data symbols and other PT-RS symbols. Another aspect of the present disclosure provides a receiver that can estimate phase error due to phase noise without knowing the sign of PT-RS symbol or the sign of IQ interference. This type of phase error estimation improves the phase noise estimation performance, and thus may improve the overall block error rate (BLER) performance at the receiver.

An apparatus may include a transmitter and one or more processors configured to identify a code rate of a low-density parity-check (LDPC) code, receive, by an LDPC encoder, a set of information bits and encode, using the code rate, the set of information bits to generate a set of encoded bits and a set of parity bits, generate, from the set of encoded bits, a matrix of bit arrays, discard one or more parity bits from the set of parity bits to generate a parity bit array with a size equal to a number of column of the matrix, generate a bit array by concatenating (1) one or more bit arrays selected from the matrix of bit arrays and (2) one or more bits selected from the parity bit array corresponding to the one or more bit arrays, and modulate, by a modulator, the bit array to generate modulated data.

Disclosed is a method comprising, by a transmitter apparatus, partitioning (901) an input data stream to obtain a bit stream X1 and a bit stream X2; subjecting (902) the bit stream X2 to encoding by LDPC encoders, to obtain X2 parity bits, and X2 information bits; applying (903) SPC encoding to the X2 parity bits, together with the bit stream X1, to obtain sign bits, wherein the bit stream X1 is used as padding bits; subjecting (904) the sign bits, the padding bits, and the X2 information bits, to an interleaver operation to obtain an interleaver output; subjecting (905) the interleaver output to Gray mapping to form multiple consecutive quadratic amplitude modulation, QAM, symbols; modulating (905) the QAM symbols by quadratic amplitude modulation to obtain a modulated data stream; and transmitting (906) the modulated data stream via a radio access network or optical fibre communication network.

The present invention discloses a communication system including WLAN communication systems comprising transmitter including an OTFS grid based Orthogonal Time Frequency Space (OTFS) waveform generator and Multiple Input Multiple Output (MIMO) streams. The transmitter comprises signal processor including OTFS modulator having FEC (forward error correction) encoder for pre-FEC bit appended input data stream and transmission of encoded input data stream in a selective sequence vide OTFS waveform modulated OTFS grid-partially loaded with QAM / PSK symbols of said encoded input data stream through MIMO transmitter and receiver streams including MIMO pre-coder based multi antenna support for said transmission and reception of said OTFS waveform thereby enabling OTFS waveform transmission and retrieval of input data stream.

In one aspect, a method described herein can be used for laser carrier recovery in optical coherent communication systems utilizing quadrature amplitude modulation (QAM) at a receiver. The method includes receiving, at the receiver, a transmitted signal modulated using QAM and a local oscillator (LO) signal. The method includes detecting, at the receiver, a phase offset between the transmitted signal and the LO signal. The method includes compensating, at the receiver, by generating an error signal based on the average power and / or voltage difference between the In-phase (I) and Quadrature-phase (Q) paths of the received signal at the receiver, where the error signal compensates for the phase offset between the transmitted signal and the LO signal.

DFT spreading is applied to a sequence of symbols to generate a DFT-spread sequence of symbols. The DFT-spread sequence of symbols is frequency-division multiplexed with a reference signal sequence to generate a multiplexed sequence, and the DFT-spread sequence of symbols and the reference signal sequence are recoverable from demultiplexing the multiplexed sequence. Further processing, such as a transform to convert to time domain and / or spectral shaping, may be applied in some embodiments. The symbols may be modulation symbols to which data bits are mapped, in binary phase-shift keying (BPSK) modulation, pi / 2-BPSK modulation, quadrature phase-shift keying (QPSK) modulation, quadrature amplitude modulation (QAM) or offset-QAM (OQAM), for example. Embodiments may be applied in conjunction with any of different types of reference signals, such as a demodulation reference signal (DM-RS), a phase tracking reference signal (PT-RS), or a channel state information reference signal (CSI-RS), or different types of reference signal sequences.

The invention discloses a WiFi-to-LoRa long-distance transmission method based on cross-protocol communication, and the method comprises the steps: carrying out the up-sampling and cyclic prefix removal of a simulated LoRa signal, carrying out the calculation of a LoRa sub-signal through an FFT algorithm, obtaining a frequency domain component of a corresponding bandwidth, and determining a to-be-used OFDM sub-carrier; selecting the closest constellation point to replace the deviated frequency domain component, and zeroing other constellation points except the constellation point corresponding to the effective subcarrier to complete QAM decoding of the LoRa signal; converting the symbols after QAM decoding into bit data, performing convolutional coding on the bit data, grouping the bit data according to preset bits, and performing QAM coding to generate corresponding QAM symbols; a plurality of QAM symbols are distributed to OFDM subcarriers at the same time, frequency domain components are converted into time domain signals through inverse Fourier transform, and long-distance transmission is carried out. According to the invention, long-distance transmission from WiFi to LoRa can be realized.

Various aspects of the present disclosure generally relate to wireless communication. Some aspects more specifically provide procedures and configurations used to perform, at a transmitter, probabilistic amplitude shaping (PAS) of quadrature amplitude modulation (QAM) communications using non-binary polar coding (NBPC). NBPC differs from binary polar coding (BPC) in that BPC uses a binary-input channel whereas NBPC uses a non-binary input channel. For example, while BPC uses a log likelihood ratio (LLR) with a single value corresponding to a given bit to be shaped, NBPC may use a probability mass function (PMF) to define or represent amplitude shaping target values. As another example, aspects use non-binary transformations, which reduce the number of passes to shape q bits from q passes (for BPC) to 1 pass (for NBPC).

The present disclosure provides a method (100) in a network device. The method (100) includes: transmitting (110) Downlink Control Information, DCI, to a terminal device, the DCI containing information from which a TBS index is derivable. The BS index is usable to determine a TBS from a set of TBSs including TBSs usable with Quadrature Phase Shift Keying, QPSK, and TBSs usable with 16-Quadrature Amplitude Modulation, 16-QAM. When the DCI is for a Narrowband Physical Downlink Shared Channel, NPDSCH, the TBSs usable with 16-QAM are determinable by the terminal device based on a deployment mode.

This disclosure provides systems, methods and apparatuses for demodulating multiple-input multiple-output (MIMO) transmissions with N layers with probabilistic shaping according to a distribution such as the Maxwell-Boltzmann distribution. A demodulator at a receiving device projects a received 4N-dimensional point to a 2N-dimensional subspace spanned by probabilistic shaping demod-equivalent receive constellation points to obtain a projected received point. The demodulator performs lattice basis reduction for a 2N-dimensional lattice to obtain a reduced basis lattice. The demodulator obtains a nearest point of the reduced basis lattice to the projected received point using linear demodulation with the reduced basis lattice.

A wireless transmission device and a wireless reception device that support QAM and APSK are used. The wireless transmission device includes a power amplifier that varies transmission power. A constellation calculation unit calculates an estimated constellation {QAM} predicted to occur when a QAM-modulated signal is amplified by the power amplifier at desired transmission power on the basis of input / output characteristics of the power amplifier, and similarly calculates an estimated constellation {APSK} predicted to occur when an APSK-modulated signal is amplified at the desired transmission power. A modulation scheme selection unit compares an estimated minimum Euclidean distance on the estimated constellation {QAM} with an estimated minimum Euclidean distance on the estimated constellation {APSK}, and selects the modulation scheme having the longer distance.

A method of a user equipment (UE) in a wireless communication system is provide. The method includes: receiving, from a base station, physical downlink shared channel (PDSCH) configuration information including a higher layer parameter for a modulation and coding scheme (MCS) table; identifying the MCS table for a PDSCH based on the higher layer parameter for the MCS table; receiving, from the base station, the PDSCH; and decoding, based on the identified MCS table, the PDSCH, wherein, in case that the higher layer parameter for the MCS table indicates a 1024-quadrature amplitude modulation (QAM), the MCS table for the PDSCH is identified as an MCS table with a maximum modulation order of 10, and wherein the MCS table with the maximum modulation order of 10 includes a set of combinations comprising a modulation order and a target code rate, the set of combinations including: (10, 805.5 / 1024), (10, 853 / 1024), (10, 900.5 / 1024), and (10, 948 / 1024).

Communication systems are described that use signal constellations, which have unequally spaced (i.e. ‘geometrically’ shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR, over the Rayleigh fading channel. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes dmin, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

The present invention discloses a highly reliable and secure transmission method based on OTFS. For a source sequence at the transmitting end, a transmission sequence is obtained after sequentially undergoing LDPC encoding, QAM mapping, SVD precoding, inverse symplectic finite Fourier transform, Heisenberg transform, R-CP addition, D / A conversion, and up-conversion, which is then transmitted via a wireless channel. After a legitimate user's receiving end obtains the received sequence, down-conversion, A / D conversion, R-CP removal, Wigner transform, symplectic finite Fourier transform, SVD decoding, single-tap equalizer processing, QAM demapping, and LDPC decoding are performed to obtain a destination sequence. The present invention achieves highly reliable physical layer secure transmission in highly dynamic communication scenarios through precoding technology based on an OTFS equivalent matrix and error control coding technology based on LDPC, thereby improving system total throughput and spectrum efficiency, and reducing system peak-to-average ratio and transmission bit error rate, while simultaneously avoiding excessive computational complexity and time-frequency resource overhead.

A QAM demodulator including a first calculation circuit including a real part returning circuit and an imaginary part returning circuit that derive, from a first complex symbol, an in phase (I) component and a quadrature phase (Q) component, respectively; first and second comparators for receiving the I and Q components, and based thereon, outputting respective bits of a bit string; first and second absolute value returning circuits that derive absolute values of the I and Q components (“abs(I)” and “abs(Q)”); first and second summers to sum each of abs(I) and abs(Q) with a first reference value and thereby provide first and second summed outputs; and a sub-QAM demodulator configured to QAM demodulate a second complex symbol and thereby output corresponding bits. I and Q components of the second complex symbol are based on the first and second summed outputs. The corresponding bits are remaining bits of the bit stream.

An apparatus includes a receiver configured to receive data, and circuitry configured to receive one or more symbols based at least on the data, determine, using the one or more symbols, an error vector magnitude (EVM) value, identify a quadrature amplitude modulation (QAM) size, determine, using the EVM value and the QAM size, a signal-to-noise (SNR) value, and adjust, based at least on the SNR value, a transmission rate of a transmitter.

Systems and methods are described herein for inserting supplemental content into a QAM signal. A unicast QAM signal between a server and a client device for delivery of content is established. The QAM signal has a particular frequency corresponding to the channel on which it will be transmitted to the client device. A request or other signal may be received from the client device requesting that supplemental content be inserted into the QAM signal. A portion of the bandwidth of the QAM signal is allocated for the supplemental content. The supplemental content is transcoded into a supplemental QAM signal in the particular frequency. The supplemental content may be packetized content such as internet protocol-based content and may be retrieved from a server or database. The supplemental QAM signal is then inserted into the unicast QAM signal using the allocated portion of the bandwidth.

The embodiment of the invention provides a simplified LLR calculation method and device suitable for a high-order QAM system, and the method comprises the steps: obtaining initial communication data, and obtaining a constellation diagram corresponding to the initial communication data; simplification is performed based on a constellation diagram, and a simplified constellation diagram is determined; determining a symmetry mode based on the simplified constellation diagram, and performing LLR calculation based on the symmetry mode to determine an LLR result; and verifying the initial communication data based on the LLR result, and determining target communication data. By virtualizing a bit region into a small number of constellation points, the computational complexity is significantly reduced.

The invention provides a communication method, device and system, and belongs to the technical field of communication, and the method comprises the steps: obtaining a bit rearrangement book table, the bit rearrangement book table comprises output bit sequences respectively corresponding to each bit rearrangement version number under different QAMs (Quadrature Amplitude Modulation), and the different QAMs comprise 16QAM, 64QAM, 256QAM, 1024QAM and 4096QAM; and determining an output bit sequence according to the bit reset list. According to the invention, the earnings of the HARQ can be effectively improved.

Methods, systems, and devices for wireless communications are described. A wireless device may encode one or more most significant bits (MSBs) of a bit sequence according to an encoding rate to generate a set of shaped bits. The bit sequence may include the one or more MSBs and one or more least significant bits (LSBs), where a quantity of the one or more MSBs that are encoded may be based on the encoding rate. The UE may map each bit of the set of shaped bits to a respective modulation symbol of a quantity of modulation symbols according to a quadrature amplitude modulation (QAM) scheme. The UE may also map the one or more LSBs to the quantity of modulation symbols according to the QAM scheme. The UE may modulate a signal based on the mappings and transmit the signal based on the modulation.

A communication method and apparatus is provided so that a fading channel can implement a good error correction capability. This helps improve information transmission reliability. The method includes: a transmit end device determines, based on N bit sets, a first sequence and a second sequence that are obtained through quadrature amplitude modulation QAM. The first sequence includes N in-phase components, and the second sequence includes N quadrature components; or the first sequence includes N quadrature components, and the second sequence includes N in-phase components, where N is an integer greater than or equal to 2. Then, the transmit end device performs interleaving processing on the first sequence, to obtain a third sequence. Then, the transmit end device sends, to a receive end device, a symbol sequence determined based on the second sequence and the third sequence. The symbol sequence includes N QAM symbols.

The present invention discloses a fiber optic nonlinear equalization method, system, device and storage medium, belonging to the field of optical transmission technology. The method includes: obtaining the M-QAM signal sequence received at the receiving end; inputting the M-QAM signal sequence into a trained bidirectional long short-term memory neural network based on a memristor array to output a score matrix; using the Viterbi algorithm to obtain the optimal label sequence corresponding to each input feature sequence according to the score matrix and the training score matrix obtained during the training process. The intermediate label values of all the optimal label sequences form the label values of the M-QAM signal sequence, and the data categories corresponding to the label values are subjected to constellation mapping to obtain the original signal sequence transmitted by the transmitting end, thus completing the nonlinear equalization. The present invention uses a memristor array to implement synaptic weights, greatly reducing the complexity of the network, and uses the bidirectional feature to process the current input information by combining the information of the previous and subsequent sequences, improving the signal quality and transmission performance.

A method of estimating a wireless channel including determining a value of β from a finite set of discrete values for channel estimation in a slot N based on time-selectivity of a channel corresponding to the slot N; estimating the channel according to reference signal symbols received in the slot N; determining a transmit power level in a slot N−1, a transmit power level in the slot N, and a power offset ratio; identifying filtered channel coefficients in the slot N−1; and computing in real time filtered channel coefficients in the slot N according to a determined set of values β applied to generate a subset of equalized QAM symbols in the slot N, the estimated channel according to reference signal symbols received in the slot N, the determined power offset ratio, and the filtered channel coefficients in the slot N−1.

The invention relates to a joint coding OTFS iterative detection method, which belongs to the field of wireless communication, and is characterized in that based on an orthogonal time-frequency-space OTFS modulation system, a coding transmitting signal of a transmitting end reaches a multi-antenna receiving end through a time-varying multipath channel; preliminarily separating received signals from different angles of arrival at a receiving end by using a multi-antenna array and beam forming; then, the separated signals pass through an iteration Dual MRC detector to obtain symbol-level detection information; symbol-level information is converted into bit-level LLR information through LLR demodulation of QAM, the bit-level LLR information is sent to a decoder, and detection and decoding are completed through continuous iteration. According to the method, the error code performance of the OTFS system is improved by using multiple antennas, beam forming, soft information exchange between the iterative Dual MRC detector and the decoder and iterative decoding.