A method of Narrow-band Internet of Things physical random-access channel (NPRACH) communication includes: transmitting, from a user equipment (UE), a Narrow-band Internet of Things (NB-IoT) Orthogonal Frequency-Division Multiple Access (OFDMA) symbol using a transmit inverse fast Fourier transform (Tx-IFFT) having a first length; processing, at lower physical layer (LPHY) of a baseband unit (BBU), the NB-IoT OFDMA symbol using a receive fast Fourier transform (Rx-FFT) having a second length different from the first length to generate an Rx-FFT output; sending, from the LPHY of the BBU to upper physical layer (UPHY) of the BBU, a selected number of values of the Rx-FFT output corresponding to desired resources block in the NB-IoT OFDMA symbol; filtering, at the UPHY, intercarrier interference (ICI) from the selected number of values of the Rx-FFT output; and reconstructing, at the UPHY, the NB-IoT OFDMA symbol.

A method for processing a multiple carrier signal provided with subcarriers distributed in a band. The method includes calculating a subcarrier noise of an edge of the band, calculating a subcarrier noise of a center of the band, calculating a ratio of the subcarrier noise of the edge of the band to the subcarrier noise of the center of the band, determining whether the ratio is greater than a threshold, and acknowledging that the edge of the band suffers from interference when the ratio is greater than the threshold.

Embodiments of the present invention disclose a reference signal transmission method, including: 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.

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.

The present disclosure relates to a method and an apparatus for reducing or eliminating interferences between resource blocks in a transmitter and/or a receiver of a filter bank multicarrier system is provided. According to at least one embodiment, the method comprises performing discrete Fourier transform (DFT) on a data symbol vector to be transmitted thereby generating a DFT-spread data symbol vector, performing a cyclic shift operation on the DFT-spread data symbol vector to arrange a small magnitude element of the DFT-spread data symbol vector at an edge of a resource block allocated to the DFT-spread data symbol vector, and performing filter bank multicarrier (FBMC) modulation on a cyclically shifted DFT-spread data symbol vector.

Various strategies and devices for same are disclosed to correct for/mitigate frequency offset (such as due to differing accuracies between an oscillator of a transmitting device and an oscillator of a receiving device) and Doppler shift (such as due to a changing relative position between a receiving device and a transmitting device). These strategies may be employed in a MIMO setting, such as, e.g. a stationary base station and a plurality of terminal devices (e.g. user devices, mobile stations, etc.), in which the transmissions for each terminal device may be associated with a different frequency offset and a different Doppler shift.

The invention relates to a method for transmitting at least K reference signals in a radio signal to be transmitted over a wireless communication system, said radio signal being intended to be emitted by an emitter comprising at least a transmit antenna configured for emitting on a number M of subcarriers S.sub.1, . . . , S.sub.M amongst which at least a number K of different subcarriers S.sub.q+1, S.sub.q+2, . . . , S.sub.q+K are contiguous, the respective frequencies of the contiguous subcarriers S.sub.q+1, S.sub.q+2, . . . , S.sub.q+K being ordered, said radio signal being provided by: inserting the at least K reference signals P.sub.1, . . . , P.sub.K so that the at least K reference signals P.sub.1, . . . , P.sub.K are respectively transmitted on the K contiguous subcarriers S.sub.q+1, S.sub.q+2, . . . , S.sub.q+K; emitting the radio signal including the at least K reference signals.

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 method and apparatus include receiving a resource allocation in a control information message. The resource allocation includes one or more resource blocks, wherein each of the one or more resource blocks comprises a plurality of subcarriers. An indication is received in the control information message identifying whether one or more guard subcarriers are present on a respective one or more of the edges of at least one resource block of the resource allocation.

An inter-carrier interference method comprises: receiving one or more OFDM signal comprising plural blocks of OFDM subcarriers of a first type and plural blocks of OFDM subcarriers of a second type, wherein the frequencies of the subcarriers of each block of OFDM subcarriers of the first type are contiguous and wherein the plural blocks of subcarriers of the first type are distributed amongst the plural blocks of subcarriers of the second type; for each of the plural blocks of subcarriers of the first type, estimating inter-carrier interference components; estimating inter-carrier interference components for the subcarriers of the second type using the inter-carrier interference components estimated for the plural blocks of subcarriers of the first type; and compensating for inter-carrier interference in the plural blocks of subcarriers of the second type using the inter-carrier interference components estimated for the sub-carriers of the second type, thereby to generate plural compensated blocks of subcarriers of the second type.