Embodiments of the present disclosure relate to a method and system to generate a waveform in a communication network. The transmitter receives an input data and transmit a generated waveform to another communication system. The input data is spread with a spread code to generate a spread data and rotated using a constellation rotation operation to produce a rotated data. The rotated data is then precoded using precoding filter to produce a precoded data, and transformed into DFT output data using DFT operation. The DFT output data is then mapped with subcarriers to generate the sub-carrier mapped DFT data and modulated using Orthogonal Frequency Division Multiplexing (OFDM) modulation to generate the waveform with low PAPR.

A multistage beamforming circuit includes a data unit that implements a frequency domain beamforming stage and a remote radio head that implements a time-domain broadband beamforming stage. The data unit implements the frequency domain beamforming stage by converting K received data streams into M precoding output streams in a frequency-domain. The data unit is configured to transform the M output streams to M OFDM time-domain signals. The remote radio head, or integrated radio unit is configured to implement a time-domain broadband beamforming stage by converting the M OFDM time-domain signals into N transmit streams of time-domain samples. The remote radio head, or integrated radio unit includes a transmit antenna array configured to transmit the N transmit streams that together form broadcast beams and user-specific beams. The antenna array includes a plurality of physical antennas. The number N of transmit streams is greater than the number M of precoding output streams.

Sounding reference signals (SRS) transmitted by a UE, e.g., for positioning or channel estimation, may be configured for one or both of frequency tone level cyclic shift and symbol level code, which, for example, enables multiplexing a greater number of UEs. The frequency tone level cyclic shift is produced by jointly processing a number of symbols with an extended cyclic shift structure. The SRS may be configured using a symbol group level that indicates the number of symbols associated with a cyclic shift structure, and an outer code that indicates a multiplier applied to the SRS at the symbol level, which increases the multiplexing opportunities. The symbol level code may further indicate an extended cyclic shift indicating a linear increase in phase rotation across tones in symbols associated with the symbol group level.

Methods, apparatus, systems and articles of manufacture to implement a signal scrambler are disclosed. An example method includes generating, by executing an instruction with a processor, a controlled random sequence based on a plurality of subcarriers and a random pulse sequence. The example method also includes forming, by executing an instruction with the processor, an output sequence by combining a source sequence with the controlled random sequence, the controlled random sequence to modify a characteristic of the source sequence in a frequency domain.

Certain aspects of the present disclosure generally relate to wireless communications. In some aspects, a wireless device reduces a peak-to-average power ratio (PAPR) of a discrete-time orthogonal frequency division multiplexing (OFDM) transmission by selecting a signal with low PAPR from a set of candidate discrete-time OFDM signals. The wireless device may generate a partial-update discrete-time OFDM signal by performing a sparse transform operation on a base data symbol sequence, and then linearly combine the partial-update discrete-time OFDM signal with a base discrete-time OFDM signal to produce an updated discrete-time OFDM signal, which is added to the set of candidate discrete-time OFDM signals. Numerous other aspects are provided.

A method and an apparatus for generating a synchronization signal in the Internet of things. In the method for generating a synchronization signal, subcarrier mapping may be performed by exchanging a signal allocated to an upper subcarrier group and a signal allocated to a lower subcarrier group among all subcarriers allocated for the synchronization signal with each other, in an in-band operation mode or a guard band operation mode of the Internet of things.

A discrete Fourier transform spread orthogonal time frequency space modulation method comprises the steps of performing DFT preceding processing and delay-Doppler domain mapping processing on the transmit data symbols, OTFS modulator, and performing delay-Doppler domain demapping processing and IDFT decoding processing on a received signal to realize demodulation; compared with the existing waveforms, including OFDM and DFT-s-OFDM, the proposed DFT-s-OTFS can reduce the bit error rate under high Doppler spread and the peak-to-average power ratio of the transmitted signal at the same time.

Embodiments of this application provide a side information transmission method and apparatus. Data to be transmitted by a transmit end includes at least one first data sub-block and at least one second data sub-block. A first modulated signal is obtained based on a first phase rotation factor. A second modulated signal is obtained based on a second phase rotation factor. Side information is generated based on the first phase rotation factor and the second phase rotation factor. The first data sub-block is carried on a first subcarrier, and the side information is also mapped to the first carrier. The first modulated signal corresponding to the at least one first data sub-block, the second modulated signal corresponding to the at least one second data sub-block, and a modulated signal corresponding to the side information are superposed to obtain a to-be-transmitted signal.

Provided is a digital filter implementing a function by using circular convolution of a digital input signal and a unit pulse response of the digital filter in applying a filter to the digital signal. In addition, a configuration sequence change of an output signal, which occurs as a result of digital filtering according to the present invention, in comparison to an input signal, is corrected by inversely performing circular shifting in a transmitter by amount of the configuration sequence change, or by reconstructing a signal after making synchronization and acquiring the signal previous to a time point of the synchronization by amount of the configuration sequence change, in a receiver.

A transmitter in a wireless communication network encodes data bits of a first layer to produce a set of coded symbols; spreads the coded symbols using discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM); and modulates the spread symbols onto a set of OFDM subcarrier frequencies to produce a discrete-time OFDM signal. Spreading is configured to map the coded symbols to a first sparse DFT-s-OFDM code space in a DFT-s-OFDM symbol, wherein the first sparse DFT-s-OFDM code space is different from a second sparse DFT-s-OFDM code space in the DFT-s-OFDM symbol, the second sparse DFT-s-OFDM code space being employed by a second layer.