Methods and apparatuses for optical communications are provided. By way of example, an optical transceiver includes a processing device coupled to a memory, an optical subassembly, and a programmable device. The optical subassembly is configured to receive and modulate a first signal carrying high speed user data for transmission to a remote device over an optical link. The programmable device is coupled to the processing device and configured to receive data relating to digital diagnostic monitoring information (DDMI) of the optical transceiver from the processing device, perform forward error correction encoding on the DDMI data to produce a remote digital diagnostic monitoring (RDDM) signal, and send the RDDM signal to the optical subassembly as a second signal to modulate for transmission. The optical subassembly is configured to current modulate the second signal on the first signal to produce a double modulated optical signal for transmission to the remote device.

A precoding method, a precoding apparatus, a Frequency Domain Equalization (FDE) method, and an FDE apparatus are provided in the embodiments of the present invention. The precoding method includes: performing offset modulation for a transmitting signal vector; calculating a precoding matrix according to the offset-modulated transmitting signal vector and a receiver decision signal vector, where the precoding matrix is used for performing precoding for the transmitting signal vector; and performing precoding for the transmitting signal vector according to the precoding matrix. Linear precoding is performed by using the offset-modulated signal on the transmitter, and therefore, the interference caused by multiple antennas and multipath propagation is reduced, the system BER is reduced, and the complexity of implementation is low.

In a base station, a setting unit for setting the number of detections sets at least one search space that includes plural control channel candidates to be targets of detection of a control signal in a terminal, and a transmission unit transmits the control signal that is mapped on any of the plural control channel candidates in the search space. Here, the number of detections in the search space by the terminal is determined based on settings of the terminal.

A method for a user equipment (UE) in a wireless communication system includes determining a coverage enhancement (CE) mode, wherein the CE mode is determined as one of a plurality of predetermined CE modes, wherein the plurality of predetermined CE modes comprise CE mode A and CE mode B; receiving downlink control information (DCI) related to scheduling a data channel, wherein a format of the DCI is related to the CE mode; and communicating the data channel based on the DCI. Further, determining the CE mode includes based on information related to indicating the CE mode being received, determining the CE mode as identical to the CE mode indicated based on the information.

A receiver for demodulating wireless signal using multiple receive antennas includes multiple signal detection modules, with each module implementing a non-interference rejection combining signal detection technique. The receiver makes a decision about whether or not to use an interference rejection combining technique, and which signal detection module to use based on the operating conditions of the received signals. When the decision is made to use an interference rejection combining technique, a single whitening filter is used to whiten the received signal prior to sending the whitened signal for processing by the signal detection module. The whitening filter may be calculated as a Cholesky decomposition of an impairment covariance matrix generated from the signals received at the multiple antennas.

Various embodiments provide for systems and methods for signal conversion of one modulated signal to another modulated signal using demodulation and then re-modulation. According to some embodiments, a signal receiving system may comprise an I/Q demodulator that demodulates a first modulated signal to an in-phase (“I”) signal and a quadrature (“Q”) signal, an I/Q signal adjustor that adaptively adjusts the Q signal to increase the signal-to-noise ratio (SNR) of a transitory signal that is based on a second modulated signal, and an I/Q modulator that modulates the I signal and the adjusted Q signal to the second modulated signal. To increase the SNR, the Q signal may be adjusted based on a calculated error determined for the transitory signal during demodulation by a demodulator downstream from the I/Q modulator.

A method and apparatus relating to feedback in a communication system. The method includes receiving feedback relating to a transmission slot; and subsequently determining the type of transmission slot the feedback relates to.

A method and apparatus for suppressing vocoder noise are provided. In the method, first information and second information are received from a channel decoder, the first information indicating whether a decoded data frame has an error and the second information being a channel quality metric, error concealment voice decoding is performed on the decoded data frame if the first information indicates that no channel decoding error has been generated and the second information is smaller than a predetermined first threshold, and normal voice decoding is performed on the decoded data frame if the first information indicates that no channel decoding error has been generated and the second information is equal to or larger than the first threshold.

According to some embodiments, a method of operation of a transmit node in a wireless communication system comprises performing polar encoding of a set of K information bits to thereby generate a set of polar-encoded information bits. The K information bits are mapped to the first K bit locations in an information sequence S.sub.N. The information sequence S.sub.N is a ranked sequence of N information bit locations among a plurality of input bits for the polar encoding where N is equivalent to a code length. A size of the information sequence S.sub.N is greater than or equal to K. The information sequence S.sub.N is optimized for the specific value of the code length (N). The method may further comprise transmitting the set of polar-encoded information bits.

Provided are methods and apparatuses for receiving information regarding modulation and demodulation in sidelink communication. The methods and apparatuses may receive configuration information on a resource pool used for sidelink transmission, receive information on an MCS (Modulation and Coding Scheme) table used for modulation of a sidelink signal among at least one MCS tables for the resource pool based on the configuration information, and perform demodulation on the received sidelink signal based on the information on the received MCS table.