Disclosed are a method and a device for transmitting data unit in a WLAN. A method for transmitting data unit in a WLAN comprises: a step of an STA generating a PPDU; and a step of the STA transmitting the PPDU to an access point (AP), wherein the PPDU comprises a first field and a second field, wherein the first field is transmitted on the basis of a first IFFT and the second field is transmitted on the basis of a second IFFT.

A system includes a hardware accelerator configured to perform a two-dimensional (2D) fast Fourier transform (FFT) on an MN element array. The hardware accelerator has log.sub.2 MN pipeline stages including an initial group of log.sub.2 M stages and a final group of log.sub.2 N stages. Each stage includes a butterfly unit, a FIFO buffer coupled to the butterfly unit, and a multiplier coupled to the butterfly unit and to an associated twiddle factor table. The hardware accelerator also includes butterfly control logic to provide elements of the MN element array to the initial group of stages in an N direction of the array, and twiddle factor addressing logic to, for the twiddle factor tables of the initial group of stages, apply an indexed entry of the twiddle factor table to the associated multiplier. The indexed entry begins as a first entry and advances by N entries after every N cycles.

A transmitter includes: a frame generator configured to generate a frame including a frame starting symbol, at least one data symbol and a frame closing symbol; a pilot and reserved tone inserter configured to insert pilots and reserved tones in at least one of the frame starting symbol, the data symbol and the frame closing symbol such that positions of the reserved tones do not overlap positions of the pilots in the at least one of the frame starting symbol, the data symbol and the frame closing symbol; and a transmitter configured to transmit the frame in which the pilots and the reserved tones are inserted, wherein the reserved tones are not used to transmit data in the frame.

An optical transmitter transmits an orthogonal frequency division multiplexing symbol in which only one-half of available subcarriers are modulated with data and the remaining subcarriers are suppressed by not modulating with data. The transmission is of duration equal to half the symbol period of the OFDM symbol, resulting in a half-cycle transmission. An optical receiver receives the half-cycle transmission OFDM symbol, regenerates the full time domain representation and recovers data modulated on the one-half of available subcarriers. The modulated subcarriers and the suppressed subcarriers alternate in the frequency domain.

Disclosed are a method and a device for transmitting data unit in a WLAN. A method for transmitting data unit in a WLAN comprises: a step of an STA generating a PPDU; and a step of the STA transmitting the PPDU to an access point (AP), wherein the PPDU comprises a first field and a second field, wherein the first field is transmitted on the basis of a first and the second field is transmitted on the basis of a second IFFT.

In 60 GHz WiGig/IEEE 802.11ad, Orthogonal Frequency Division Multiplexing (OFDM) is used to achieve higher throughput. However, OFDM has one problem of high Peak-to-Average Power Ratio (PAPR) caused by the summing up of the large number of subcarriers. A high PAPR signal degrades the efficiency of power amplifier (PA) and may cause spurious emissions because of the PA non linearity. In order to reduce PAPR, Generalized Frequency Division Multiplexing (GFDM) which has the characteristics of both single carrier and multi carrier transmission has been studied. By introducing GFDM, the number of subcarriers can be decreased while still maintaining a high throughput.

There is provided a method comprising: obtaining, by an apparatus, a first data block, a second data block and a third data block; generating a first signal, wherein a first part of the first signal is generated based on a data of the first data block, and wherein a second part of the first signal is generated based on a data of the second data block, the second part being subsequent in time domain compared with the first part; generating a second signal, wherein a first part of the second signal is generated based on a data of the third data block, and wherein a second part of the second signal is generated based on the data of the second data block, the second part being subsequent in time domain compared with the first part; and transmitting the first and second signals.

The invention relates to a method for reducing the PAPR in FRFT-OFDM systems, which belongs to the field of broadband wireless digital communications technology. The method is based on fractional random phase sequence and fractional circular convolution theorem, which can effectively reduce the PAPR of the system. The method of the invention has the advantages of simple system implementation and low computational complexity. In this method, the PAPR of the system can be effectively reduced while maintaining the reliability of the system. When the number of candidate signals is the same, the PAPR performance of the present method was found to be almost the same as that of SLM and better than that of PTS. More importantly, the present method has lower computational complexity than that of SLM and PTS methods.

The present disclosure provides a multi-carrier time-division multiplexing (MC-TDMA) modulation and demodulation method and system. Before multi-carrier modulation is performed on an input symbol, an interleaving allocation and an FFT may be performed, a time domain symbol may be transformed into a frequency domain symbol signal to perform a MDFT treatment. A sending end may adopt an analyzing filter bank structure, and pre-filtering and an IFFT may be performed on a signal successively. A pre-filter may be positioned between an NM point FFT and an M point IFFT, a PAPR value of the system may be reduced using the symmetry of a coefficient of a filter, and a frequency domain symbol signal may be allocated to different sub-bands for multi-carrier modulation.

Methods and apparatuses for UE initiated reporting in a wireless communication system. A method of operating a UE includes: transmitting UE capability information supporting a FTN; generating data modulation symbols including a set of zero symbols, wherein the data modulation symbols are up-sampled or zero-padded; performing, to obtain DFT output signal, a DFT spread operation on the up-sampled or the zero-padded data modulation symbols; performing, based on a target FTN compression rate and a SC allocation, a discarding or a down sampling operation on the DFT output signal, wherein the discarding or the down sampling operation generates a subset of DFT symbols; mapping the subset of DFT symbols to a set of SCs; and performing an IFFT operation on the subset of DFT symbols to obtain an FTN-DFT-S-OFDM signal including the target FTN compression rate comprising a positive rational number smaller than one.