Disclosed is a method for a station (STA) device transmitting data in a Wireless Local Area Network (WLAN) system. The method for transmitting data, according to one embodiment of the present invention, comprises the steps of: FEC encoding transmission data; interleaving the transmission data; constellation mapping the transmission data; performing IDFT on the transmission data; and upconverting the transmission data and transmitting a transmission signal, wherein IDFT is performed using different FFT sizes for a first part of the transmission signal and a second part of the transmission signal, and the second part of the transmission signal is allocated to at least one STA in units of at least one resource unit.

We disclose an optical add-drop multiplexer that can apply different routing operations to different subcarriers of a data frame. In an example embodiment, the digital signal processor (DSP) of the optical add-drop multiplexer carries out subcarrier-specific add, drop, and pass-through operations in the electrical frequency domain, which enables the DSP to only partially unwrap the pass-through subcarriers, thereby at least partially avoiding some of the more processing-power-hungry DSP operations and reducing the sub-wavelength routing latency accordingly. Also disclosed is an example data-frame structure that can be used to provide subcarrier-specific routing instructions to the optical add-drop multiplexer.

An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.

A technique for Bluetooth wireless communication is described. According to one aspect of the technique, Bluetooth data from a data source is received in a first wireless device through an antenna and a Bluetooth radio frequency transceiver thereof via a Bluetooth connection with the data source. The Bluetooth data is used to generate a modulation signal according to a narrowband orthogonal multi-carrier modulation technology. The modulation signal is transmitted to a second wireless device through the antenna and the Bluetooth radio frequency. The antenna and the Bluetooth radio frequency transceiver are time-multiplexed by the Bluetooth connection between the first wireless device and the data source, and the wireless connection between the first wireless device and the second wireless device. The described technique can be advantageously used for expanding the distance of Bluetooth wireless propagation of Bluetooth devices.

A signal processing method in a digital-domain includes: adding a random number sequence signal into a time-domain input signal to generate a time-domain processed input signal; performing a Fourier transform operation upon the time-domain processed input signal to generate a frequency-domain processed input signal; performing an equalizer operation upon the frequency-domain processed input signal to generate a frequency-domain output signal according to coefficients of the equalizer operation; performing an inverse Fourier transform operation upon the frequency-domain output signal to generate a time-domain output signal; generating a decision output signal and generating a time-domain error signal according to the time-domain output signal; and determining the coefficients according to the time-domain error signal and the frequency-domain processed input signal.

A technique for transmitting data from a passive radio device (100) is described. As to a method aspect of the technique, an antenna (102) of the passive radio device (100) is exposed to an incident radio signal (502). A frequency domain representation of the incident radio signal (502) comprised at least one muted gap between active subcarriers within a bandwidth of the incident radio signal (502). The incident radio signal (502) is backscattered from the antenna by modulating an impedance of the antenna according to the data using at least two different modulation frequencies that differ by less than the bandwidth.

The apparatus of wireless communication is a UE and a base station. The UE received a control information indicating a reference signal (RS) mode for a non-coherent transmission of an UCI to the base station. The UE in the RS mode may map an RS according to an RS pattern and the UCI into resource elements assigned for a PUCCH to transmit the UCI and transmit an uplink control signal including the RS and the UCI to the base station over the PUCCH. The UE may determine a RS pattern and puncture the resource elements mapped with the code point of the UCI that corresponds to the RS pattern and map the RS based on the RS pattern. The UE may map the RS based on the RS pattern and map the code point by rate matching around the resource into which the RS is mapped.

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 for the reserved tones; 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; re-arranging an order of the preliminarily determined carrier indices of the reserved tones; calculating comparison reference average values of kernel signals generated by changing each of the re-arranged carrier indices of the reserved tones, and finally determining carrier indices of the reserved tones which generate a kernel signal having the smallest comparison reference average value among the comparison reference average values as indices of the reserved tones.

Embodiments herein provides a method and apparatus for data communication in an OFDM system. The method comprising receiving by a second OFDM apparatus a plurality of parameters, a signal comprising data and at least one of a Reference Signal (RS) and a message from a first OFDM apparatus. The plurality of parameters comprises at least one of a numerology of the first apparatus, a numerology of the second apparatus, a ratio of numerology of the first apparatus to the second apparatus and a measurement window. The method includes filtering a desired band comprising the at least one of the RS and the message from the received signal, removing a cyclic prefix from the filtered signal, and decoding at least one of the RS and the message from the signal with adjusting a circular shift in the set of symbols based on the plurality of parameters.

Methods, apparatus, and systems for reducing Peak Average Power Ratio (PAPR) in signal transmissions are described. In one example aspect, a wireless communication method includes determining, for a time-domain sequence x(i), an output sequence s(k). The output sequence s(k) is an inverse Fourier transform of a frequency-domain sequence S(j), and S(j) represents a dot-multiplication of a frequency-domain sequence Y(j) corresponding to the time-domain sequence x(i) and a frequency-domain sequence Z(j) corresponding to a three-coefficient function associated with

[00001]$\frac{\sqrt{2}}{2},$

1, and

[00002]$\frac{\sqrt{2}}{2}.$

The method also includes generating a waveform using the output sequence s(k), where i is from 0 to I−1, j is from 0 to J−1, k is from 0 to K−1, and I<J<=K.