Dual sub-carrier modulation (DCM) is introduced in high efficiency (HE) WLAN. DCM is a solution to deal with narrow band interferences and for range extension. DCM can introduce frequency diversity into OFDM systems by transmitting the same information on two subcarriers separated in frequency. If DCM is applied, then the transmitter modulates the same encoded bits onto two separated subcarriers with the same or different constellation mapping schemes. DCM suffers from a high peak-to-average power ratio (PAPR). In accordance with one novel aspect, a method of transmitting and encoding a HE PPDU frame with binary phase shift keying (BPSK) DCM and lower PAPR is proposed.

Systems and methods are provided for peak to average power ratio (PAPR) reduction in multichannel digital front-ends (DFEs). A transmitter may be configured to reduce PAPR during multichannel transmission, with the reducing comprising: generating a plurality of frequency-domain symbols, each of which corresponding to a particular one of a plurality of subcarriers; assigning the subcarriers to a plurality of channels, wherein a number of channels is less than a number of subcarriers; and generating a plurality of time-domain signals corresponding to the channels. An adjustment to reduce PAPR may be applied to at least one of the time-domain signals, with the adjustment being based on symbols boundaries. The adjustment may comprise sign inversion. Adjusted and unadjusted waveforms may be generated for two or more of the time-domain signals; and selection may be made between generated adjusted waveforms based on particular criteria. The criteria may comprise lowest peak.

An apparatus for a wireless communication system is to transmit a reference signal on a common set of resource elements, REs, the common set of REs used by one or more further apparatuses in the wireless communication system to transmit the reference signal so that the reference signals of the apparatus and of the one or more further apparatuses use the same REs. The reference signal is transmit using OFDM symbols and the same sequence having a zero auto correlation property is applied to each OFDM symbol. A phase correction is applied to an OFDM symbol before transmission, wherein a correction factor of the phase correction depends on a comb factor and a comb offset of the OFDM symbol and is independent of the resource element.

Disclosed are a multi-carrier superposition method and device. First, input carrier signals arc superposed, and gain reduction processing is conducted during the superposition process, and then CFR processing and increase processing are conducted on the superposed carrier signals. Thus, under the circumstance of multi-carrier superposition, it can be effectively ensured that signals cannot overflow, and meanwhile the requirement for precision of a system during processing is met.

Disclosed is a an apparatus for reducing a reducing a peak to average power ratio (PAPR) for layer division multiplexing (LDM) in an orthogonal frequency division multiplexing (OFDM) system, the apparatus may include a peak remover configured to detect a peak power value of a subcarrier signal that is input and generate a peak removal signal that decreases the detected peak power value, and a processor configured to perform constellation remapping on a first signal generated by combining the subcarrier signal and the peak removal signal and then generate a second signal into which additional data is inserted.

The present invention discloses an apparatus and a method for determining a subband resource and relates to the field of communications network technologies, so as to resolve a problem of how to ensure communication between user equipment and a base station while costs of the UE or complexity of the UE is reduced. In embodiments of the present invention, subband resource information acquired by UE is used to determine a subband resource, so that data and/or control information can be transmitted according to the subband resource. The solutions provided in the embodiments of the present invention are suitable to be used to determine a subband resource.

A method for transmitting a signal is described, wherein the method has transforming a signal into a frequency domain to obtain a spectrum, forming a filtered spectrum according to a filter spectrum and occupying a set of subcarriers of a frequency domain representation of an Orthogonal Frequency Division Multiplex (OFDM) signal with the filtered spectrum. A temporary signal is obtained by transforming the frequency domain representation of the OFDM signal into a time domain. The temporary signal is subjected to a phase modulation.

A transmitter for transmitting data to communications devices via a wireless access. The transmitter including modulator circuitry configured to receive modulation symbols of a segment and to rotate each modulation symbol by an angle dependent on a choice of modulation scheme, and receive each of the segments of rotated modulation symbols and for each segment to separate real and imaginary components of the rotated modulation symbols for the segment and to interleave the real components of the rotated modulation symbols of the segment differently to the imaginary components of the rotated modulation symbols of the segment. The circuitry also is configured to recombine the real and imaginary interleaved components of the rotated modulation symbols of each segment and to form from the real and imaginary components modulation cells.

Various aspects relate generally to the generation and wireless transmission of a long training field (LTF) and a data field within a 320 MHz or 240 MHz bandwidth channel. The LTF includes an LTF sequence based on a concatenation of a plurality of LTF subsequences, each LTF subsequence being associated with a channel bandwidth less than the total bandwidth of the channel, each of the plurality of LTF subsequences being selectively phase-rotated to reduce a peak-to-average power ratio. Each of the plurality of LTF subsequences may be associated with an LTF designed for an 80 MHz bandwidth channel. The LTF and the data field may then be transmitted in a wireless packet to at least one second wireless communication device via the 320 MHz or 240 MHz bandwidth channel.

The application provides a short training sequence design method and apparatus. The method includes: determining a short training sequence, where the short training sequence may be obtained based on an existing sequence, and the short training sequence with comparatively good performance may be obtained through simulation calculation, for example, by adjusting a parameter; and sending a short training field on a target channel, where the short training field is obtained by performing inverse fast Fourier transformation IFFT on the short training sequence, and a bandwidth of the target channel is greater than 160 MHz.