A method of designing a digital filter for example for use in an FBMC/OQAM telecommunications system, with a target overlapping factor and meeting a specified signal to interference ratio is described, whereby a candidate filter design defined by an impulse response, satisfying the Nyquist criterion and having an overlapping factor higher than the target is selected, and the time and frequency coefficients of its impulse response inverted to define a new filter design; and truncating the impulse response defining said new filter design to the minimum number of coefficients achieving said specified signal to interference ratio.

Signal extrication of a pair of quadrature amplitude modulated signals of a particular carrier frequency and phase constant by equally splitting all input signals into two independent circuit paths that contain identical components but one independent circuit path performs a complementary signal processing function with respect to the other resulting in a counterbalance between the two paths, canceling all output signals with the exception of said pair of quadrature amplitude modulated signals which are not canceled because of the singular signal nullification property of a product detector circuit that is a component in each of said independent circuit paths.

An OFDM transmitter and an OFDM receiver respectively transmit and receive N (N?2, N is an integer) control symbols. For each control symbol, a guard interval time-domain signal is, for example, identical to a signal obtained by frequency-shifting at least a portion of a useful symbol time-domain signal by an amount different from any other symbol, or to a signal obtained by frequency-shifting one or both of a portion and a span of a useful symbol interval time-domain signal different from any other symbol by a predetermined amount.

Methods, systems, and devices for wireless communications are described. A transmitting device may modulate a first binary sequence using binary phase shift keying on a first axis of a complex plane. The device may modulate a second binary sequence using binary phase shift keying on a second plane of a complex axis. The first axis and the second axis may be orthogonal. The device may transmit the first binary sequence and the second binary sequence according to the modulation of the first binary sequence and the second binary sequence.

An apparatus and method for filter bank multi-carrier signal modulation with a low peak-to-average power ratio (PAPR) in a multiple antenna system are disclosed. According to embodiments of the present disclosure, in a multiple antenna transmission method, after a plurality of transmission candidate signals, which are modulated for each antenna using discrete Fourier transform (DFT) spread filter bank multi-carrier and offset quadrature amplitude modulation (FBMC/OQAM) techniques and are capable of obtaining a single carrier effect, are generated, a transmission candidate signal with a low PAPR can be selected and transmitted, and thus peak-to-average power ratio performance can be effectively improved, and interference between subcarriers can be eliminated by applying an Alamouti coding manner.

An input selector for selecting an input of a convolution encoder of a transmitter is disclosed. The input selector comprises a shaper block and an input-select block. The shaper block is configured to receive an input comprising a first number of input bits, the shaper block configured to generate a shaped bit stream corresponding to the first number of input bits. The input-select block is configured to generate an encoder input bit stream for the encoder based on the shaped bit stream, wherein the input-select block generates the encoder input bit stream such that, when input into the encoder, a first bit of the encoder input bit stream sets a state of the encoder in order that a subsequent second bit of the encoder input bit stream causes the encoder to generate a bit of the shaped bit stream at a pre-determined position in an encoder output bit stream.

Provided are a pilot signal transmission method and apparatus, and a transmitting terminal. The method includes: setting a first pilot signal, a second pilot signal, and a third pilot signal on a same subcarrier; and transmitting the first pilot signal, the second pilot signal, and the third pilot signal respectively on three continuous symbols on the same subcarrier. The first pilot signal, the second pilot signal, and the third pilot signal are all nonzero data, a phase difference between the first pilot signal and the second pilot signal is 90 degrees, a phase difference between the third pilot signal and the second pilot signal is 90 degrees, and a phase difference between the first pilot signal and the third pilot signal is 180 degrees.

A radio base station that communicates with a user terminal, and has a control section that executes control so that signals are time-division-multiplexed over a first radio resource region where symbols are multiplexed at a rate equal to or below a Nyquist rate and a second radio resource region where symbols are multiplexed at a faster rate than the Nyquist rate. The radio base station also includes a transmission section that transmits the signals that are time-division-multiplexed in the first radio resource region and the second radio resource region, to the user terminal to reduce the interference against predetermined signals in a radio communication system in which Faster-Than-Nyquist (FTN) is used.

Receivers for coded orthogonal frequency-division multiplexed (COFDM) signals conveying the same coded data both in lower-frequency and upper-frequency sidebands thereof. Apparatus for performing a complex synchrodyne of COFDM signal to baseband is followed by apparatus for extracting the COFDM subcarriers of the lower-frequency and upper-frequency sidebands of the COFDM signal from the in-phase and quadrature-phase results of the complex synchrodyne. The COFDM subcarriers of the lower-frequency sideband as converted to baseband are supplied to apparatus for demodulating and demapping those subcarriers to recover a first set of coded data. The COFDM subcarriers of the upper-frequency sideband as converted to baseband are supplied to apparatus for demodulating and demapping those subcarriers to recover a second set of coded data. A diversity combiner combines the first and second sets of coded data for subsequent decoding.

Prior-art receivers for double-sideband coded orthogonal frequency-division modulation (COFDM) signal, such as receivers for digital television (DTV) broadcasting, have folded the frequency spectrum in half by synchrodyne to baseband before discrete Fourier transform (DFT) and de-mapping quadrature amplitude-modulation (QAM) of COFDM signal subcarriers, thus to improve signal-to-noise ratio by 6 dB. Single-sideband or independent-sideband COFDM receivers that perform DFT and demapping of QAM of COFDM signal subcarriers in an unfolded frequency spectrum can improve signal-to-noise ratio by 8.5 dB by maximal-ratio combining bits of demapping results. Such improvement is achieved even when such a receiver is arranged for receiving a DSB-COFDM signal, in which double-sideband signal the frequency spectra of the lower and upper sidebands mirror each other. Reception range is increased by about a third over that of receivers which fold the frequency in half during synchrodyne to baseband. Such increase in reception range is particularly important for DTV receivers using indoor antennas.