Systems, methods, and devices are provided for reducing and/or eliminating impact of inter-carrier interference on wireless signals transmitted and received via off-grid radio communications (e.g., Device-to-Device (D2D) communication). The method may include using circuitry to generate a plurality of subcarriers associated with a data signal, such that the plurality of subcarriers transmit the data signal along a narrowband transmission channel. The method may involve using the circuitry to remove a null subcarrier of the plurality of subcarriers that is located at a direct current (DC) frequency. The method may also involve generating an asymmetrical frequency spectrum for a portion of the plurality of subcarriers centered about the removed null subcarrier. The method may also include transmitting the plurality of subcarriers to another electronic device via D2D communication.

Apparatuses and methods for performing asynchronous multicarrier communications are provided. One such method involves generating, at a first wireless device, a waveform including one or more carriers, shaping the waveform to reduce interference between the waveform and adjacent waveforms, and transmitting, on a spectrum, the shaped waveform asynchronously.

Aspects of the subject disclosure may include, for example, obtaining data regarding interference detected in a received communication signal, and performing polarization adjusting by rotating one or more radiating elements of an antenna system such that an impact of the interference on the antenna system is minimized. Other embodiments are disclosed.

A system that incorporates aspects of the subject disclosure may perform operations including, for example, receiving, via an antenna, a signal generated by a communication device, detecting passive intermodulation interference in the signal, the interference generated by one or more transmitters unassociated with the communication device, and the interference determined from signal characteristics associated with a signaling protocol used by the one or more transmitters. Other embodiments are disclosed.

A transmitter using a channel aggregation in which available channels existing in various frequency bands are bound and transmitted and using an Orthogonal Frequency Division Multiplexing (OFDM), an Orthogonal Frequency Division Multiple Access (OFDMA), or a system similar to them as a modulation system. One or a plurality of transmission units are provided in parallel, and one or a plurality of transmission processing units are provided in parallel. The transmission processing unit has an inverse fast Fourier transforming circuit or a discrete inverse Fourier transforming circuit, a GI and overlap margin (OM) insertion circuit, and a time-domain windowing processing unit. The time-domain windowing processing unit multiplies a universal time-domain window function in accordance with a spectrum mask and transport electric power which are required in each channel, thereby suppressing out-of-band radiation electric power every channel. A kind and a window transition duration of the time-domain window function can be arbitrarily set every channel.

Provided are an apparatus for supporting a plurality of wireless communication systems and an operating method of the same. The apparatus receives an integrated signal including a first wireless communication system signal and a second wireless communication system signal assigned to a certain frequency band, performs first processing on the integrated signal, performs second processing on the integrated signal, is scheduled to perform at least one of first interference cancellation (IC) process of canceling interference of the first wireless communication system signal from the integrated signal based on the signal on which first processing is performed or second IC process of canceling interference of the second wireless communication system signal from the integrated signal based on the signal on which second processing is performed, and performs at least one of the first IC process or the second IC process based on the scheduling.

A frequency-selective system that may be used as, or as part of, an add/drop multiplexer. An input signal is fed to a Mach-Zehnder interferometer configured to drop, or suppress, by destructive interference, a signal component in a first frequency band from among a plurality of frequency bands. One or more bandpass filters in one arm of the Mach-Zehnder interferometer suppress other frequencies, outside of the first frequency band, so that signals at these other frequencies are not suppressed by destructive interference and are present at the output of the Mach-Zehnder interferometer. A coupler connected after the output of the Mach-Zehnder interferometer adds, into the signal path, a replacement for the dropped signal.

Embodiments include digital signal processing units, a transmitting device for a wireless communication system and methods of processing a composite time domain signal having a plurality of parallel and independent signals that collectively form a parallel communication. It is proposed a new waveform configuration suitable for 5G and that is able to reduce out-of-band (OOB) emissions which are received on a first time domain signal associated to a first sub-band where the OOB emissions originate from an OFDM time domain signal associated with a second sub-band adjacent to the first sub-band. The proposed solution is partly based on filtered-OFDM with the exception that sub-band filtering is not performed on all the samples of the stream of OFDM symbols. Instead, filtering is performed only, for each OFDM time domain signal, where transition occurs between consecutive OFDM symbols.

A reference signal transmission method includes: sending, by a terminal, a first reference signal and a second reference signal; and correspondingly, receiving, by a network device, the first reference signal and the second reference signal, where the first reference signal is mapped to a plurality of symbols and is used for estimation of channel state information, the second reference signal is mapped to at least two of the plurality of symbols and is used for phase tracking, and a subcarrier to which the second reference signal is mapped on one of the at least two symbols has a same frequency-domain location as a subcarrier to which the second reference signal is mapped on the rest of the at least two symbols. With the foregoing solution, accuracy of channel state information estimation can be improved.

Embodiments of the present invention disclose a signal transmission method, including: sending, by a first device, a first reference signal to a second device, where the first reference signal is used for phase tracking; the first reference signal is mapped to a first symbol; the first symbol includes a symbol that carries a data signal and that precedes a second symbol; the second symbol is one or more consecutive symbols carrying a DMRS; and the one or more symbols include the 1.sup.st symbol carrying the DMRS. According to the foregoing solution, it can be ensured that a PT-RS is also mapped to a symbol to which a data channel is mapped and that precedes a symbol carrying a DMRS, thereby ensuring phase noise estimation performance.