A communication device comprises a receiver including at least two receive antennas and configured to receive at least one reference signal of a plurality of reference signals, each reference signal being transmitted from at least one base station at a predefined reference signal transmission time; a controller configured to switch between at least two receive configurations of the at least two antennas during a reception period of the at least one reference signal; and a signal quality determiner configured to determine a parameter indicative of a first signal quality of the received reference signal for each receive configuration.

A wireless communication device can include an antenna configured to sense a radio frequency (RF) signal. The wireless communication device can include signal estimation circuitry configured to generate estimates of amplitude and frequency for unmodulated spurs within the RF signal. The wireless communication device can further include multi-tone generator circuitry coupled to the signal estimation circuitry and configured to generate a composite spur cancellation signal based on the estimates of amplitude and frequency for unmodulated spurs within the RF signal. The wireless communication device can further include adder circuitry configured to subtract the spur cancellation signal from the RF signal to generate a spur cancelled signal.

A fading assessment unit 34 assesses the degree of fading of a received radio wave. An SNR calculation unit 33 calculates an SNR value of a signal based on the radio wave. A communication mode determination unit 35 determines the communication mode of communication from a transmission side of the radio wave on the basis of the result of the assessment by the fading assessment unit 34 and the SNR value calculated by the SNR calculation unit 33.

A digital circuit for implementing a channel-tracking functionality, in which an adaptive (e.g., FIR) filter is updated based on reinforcement learning. In an example embodiment, the adaptive filter may be updated using an LMS-type algorithm. The digital circuit may also include an electronic controller configured to change the convergence coefficient of the LMS algorithm using a selection policy learned by applying a reinforcement-learning technique and based on residual errors and channel estimates received over a sequence of iterations. In some embodiments, the electronic controller may include an artificial neural network. An example embodiment of the digital circuit is advantageously capable of providing improved performance after the learning phase, e.g., for communication channels exhibiting variable dynamicity patterns, such as those associated with aerial copper cables or some wireless channels.

A wireless communication device can include an antenna configured to sense a radio frequency (RF) signal. The wireless communication device can include signal estimation circuitry configured to generate estimates of amplitude and frequency for unmodulated spurs within the RF signal. The wireless communication device can further include multi-tone generator circuitry coupled to the signal estimation circuitry and configured to generate a composite spur cancellation signal based on the estimates of amplitude and frequency for unmodulated spurs within the RF signal. The wireless communication device can further include adder circuitry configured to subtract the spur cancellation signal from the RF signal to generate a spur cancelled signal.

A communication device comprises a receiver including at least two receive antennas and configured to receive at least one reference signal of a plurality of reference signals, each reference signal being transmitted from at least one base station at a predefined reference signal transmission time; a controller configured to switch between at least two receive configurations of the at least two antennas during a reception period of the at least one reference signal; and a signal quality determiner configured to determine a parameter indicative of a first signal quality of the received reference signal for each receive configuration.

An apparatus to transmit and receive wireless communications is disclosed in which the transmit circuitry includes a square root raised cosine filter to pulse shape modulate signals and the receive circuitry includes a higher order Nyquist receive filter coupled to receive the input signals and remove the pulse shaping modulation. The cascaded combination of the transmit and receive filters has a frequency response equivalent to a higher order generalized raised cosine filter response.

A signal processing method, a signal filtering apparatus, and a signal processing apparatus are provided. An input signal may be input into a filter having a passband, a superfluous signal of the passband may be output from the filter, and a target signal may be obtained by subtracting the superfluous signal from the input signal.

Systems and methods of transmitting direct detection optical signal are provided. A direct detection optical transmitter according to illustrative embodiments includes a Mach Zehnder Modulator (MZM) configured to modulate laser light based on an electrical drive signal to generate a modulated optical signal and a complementary-modulated optical signal. The optical transmitter includes an optical finite impulse response (FIR) filter configured to receive the complementary-modulated optical signal and generate a filtered optical signal. The optical transmitter includes a polarization rotator configured to receive the filtered optical signal and output a rotated optical signal. The optical transmitter includes an optical combiner configured to combine the modulated optical signal and the rotated optical signal. The optical transmitter includes an output port configured to output the combined optical signal.

The present invention provides a signal modulation method. The method includes: generating a transmit signal pulse waveform, where a width of the pulse waveform is , each pulse waveform is associated with n symbols (n>1), a width of each symbol is , and $=\frac{}{n};$
performing an operation on every n consecutive symbols in a to-be-sent symbol flow and the pulse waveform according to a preset operation manner, to generate an associated signal of the symbols and the pulse waveform; and sending the associated signal by using a transmission channel. The present invention helps improve spectral efficiency of a system. In addition, symbols are mutually constrained based on a correlation between the symbols, and information symbols are scattered to a plurality of symbols, thereby helping improve a capability of resisting noise and attenuation by a signal.