An OFDM modulation device includes a communication use specifying unit to specify a communication use of a communication frame, a header generating unit to generate a header of the communication frame in which communication use specifying information indicating the communication use specified by the communication use specifying unit is stored, a payload generating unit to generate a payload of the communication frame, and an inverse fast Fourier transform unit to generate a communication frame of time domain by executing an inverse fast Fourier transform of a size corresponding to the communication use specified by the communication use specifying unit on data of frequency domain including the header generated by the header generating unit and the payload generated by the payload generating unit.

An OFDM signal transmission apparatus is provided, which includes a mapping unit configured to map first signals into N subcarriers and second signals into M subcarrier(s) to form an OFDM signal, wherein N is larger than M. The first signals are each indicating a same bit of retransmission information and the second signals are each indicating a same bit of information other than retransmission information. The OFDM signal transmission apparatus further includes a transmitting unit configured to transmit the formed OFDM signal.

Proposed are a method and a device for transmitting a signal including a data field in a wireless LAN. For example, an access point (AP) allocates, to a second station, a second frequency band adjacent to a first frequency band, wherein the second frequency band can include a plurality of resource units. In addition, a signal including the data field can be transmitted to the second station through the allocated second frequency band. Furthermore, when the first frequency band is allocated to the first station, the AP can allocate, to the second station, as a null resource unit, a resource unit adjacent to the first frequency band among the plurality of resource units.

Wireless communications systems and methods related to cross Component Carrier (CC) transmission are provided that assist in minimizing PAPR. A first wireless communications device repeats data across multiple CCs in order to increase coverage while maintaining power levels within approved limits. In order to reduce PAPR, a number of different methods and mechanisms may be used. Rate matching may be performed across the multiple CCs as though a single virtual BWP. Alternatively, each copy of the data on its separate CC may be modified differently in some way, such as by using different scrambling IDs or different redundancy versions. Additionally, when utilizing DFT-s-OFDM modulation, an alternative method is provided which may lower PAPR. The DFT method includes performing a DFT on the combined data, tone mapping to each of the carriers, and performing an IFFT for each carrier individually. Each IFFT may be different than the other.

An OFDM (orthogonal frequency division multiplexing) transmitter includes an inverse fast Fourier transform circuit, which, in operation, generates, based on digital input data, a complex time-varying digital signal having real and imaginary components; and a multiplexer adapted to generate a time-multiplexed digital signal by time-multiplexing one or more of the real components with one or more of the imaginary components.

System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

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.

A WLAN baseband chip and an FDMA PPDU generation method are disclosed. The WLAN baseband chip obtains a subcarrier coefficient corresponding to a subcarrier set, m LDR SYNC sequences, and n−m HDR SYNC sequences. The WLAN baseband chip performs duplicating processing on m data streams in n data streams, to obtain m data sequences on which the duplicating processing has been performed and n−m remaining data streams. The WLAN baseband chip obtains m pieces of to-be-modulated data based on the m LDR SYNC sequences and the m data sequences on which the duplicating processing has been performed, and obtains n−m pieces of to-be-modulated data based on the n−m HDR SYNC sequences and the n−m remaining data streams, to obtain n pieces of to-be-modulated data. The WLAN baseband chip performs postprocessing to obtain a frequency-domain symbol sequence, to obtain an FDMA PPDU.

A method of determining reserved tones to be used for reduction of a peak to average power ratio (PAPR) of a signal includes: randomly selecting carrier indices for the reserved tones and generating a kernel signal based on the randomly selected carrier indices; calculating a comparison reference average value of the kernel signal, comparing the calculated comparison reference average value with a prestored comparison reference average value, and preliminarily determining carrier indices of the reserved tones based on the comparison; randomly re-arranging an order of the preliminarily determined carrier indices of the reserved tones; and calculating the comparison reference average value while changing each of the re-arranged indices of the reserved tones, and finally determining carrier indices for which the calculated comparison reference average value becomes the smallest value as carrier indices of the reserved tones.

In a transmission device, a signal processing circuit generates an aggregate physical layer convergence protocol data unit (A-PPDU) by adding a guard interval to each of a first part of a first physical layer convergence protocol data unit (PPDU) transmitted over each of a first through L′th channel of a predetermined channel bandwidth, where L is an integer of 2 or greater, a second part of the first PPDU transmitted over each of an (L+1)′th through P′th channel, which is a variable channel bandwidth that is N times the predetermined channel bandwidth, where N is an integer of 2 or greater and P is an integer of L+1 or greater, and a second PPDU transmitted over the (L+1)′th through P′th channel. A wireless circuit transmits the A-PPDU.