An optical signal transmission apparatus includes a modulation unit which modulates a transmission signal, a training signal sequence generation unit which generates a plurality of signal sequences having power concentrated in a plurality of different frequency bands, at least one of an amplitude and a phase of the plurality of signal sequences being modulated, as a training signal sequence, a signal multiplexing unit which appends the training signal sequence to the transmission signal, and an electro-optical conversion unit which converts a signal sequence obtained by appending the training signal sequence to the transmission signal into an optical signal and transmits the optical signal.

The present invention relates to a method and apparatus in a digital communication system that employs phase-aided adaptive modulation to overcome phase noise impairments. The transceiver is configured to transmit a message comprising channel symbols from a primary and a secondary set of channel symbols, wherein the primary set of channel symbols comprises channel symbols having different phase with respect to one another and the secondary set of channel symbols comprises only channel symbols with a fixed known phase.

Aspects are provided which allow for a network entity such as a base station to configure odd modulation orders to be applied to downlink or uplink transmissions via signaling between the network entity and the UE. Initially, the network entity transmits a configuration to the UE indicating network support for communications using odd order modulation. Afterwards, the UE transmits, and the network entity receives, data in a signal using the odd order modulation. As a result, improved SPEF, PAPR reduction, and phase noise mitigation associated with odd order modulations may be realized through application of odd order modulations to data transmissions or receptions based on network support being configured for such odd order modulations.

Quadrature Amplitude Modulation (QAM) methods, apparatus, and systems are disclosed.

Methods and apparatus for wired communications are disclosed. A method for transmitting a data stream through a wired communications channel includes encoding the data stream to produce a first baseband modulating signal I(t) and a second baseband modulating signal Q(t) whose amplitudes together represent a time series of complex symbols (I, Q) each selected from a two-dimensional (2-D) constellation of symbols distributed on the phase plane about the origin such that at least one of the baseband modulating signals has a substantially non-zero mean amplitude, modulating the baseband signals I(t) and Q(t) to produce a modulated signal, wherein the I(t) and Q(t) components of the modulated signals are generally fixed in quadrature, and providing the modulated signal to a wired communications channel.

A Radio Network Node (RNN) 110 and a method therein for improving capacity in a wireless communications system 100. The RNN is configured to serve a first wireless device 120 and a second wireless device (WD) 130. The RNN assigns a shared uplink pilot signal to the first and second WDs. Further, the RNN transmits, to the first WD, an indication of how possible second data intended for the second WD will be comprised in a signal to be transmitted to the first WD. Furthermore, the RNN estimates a combined channel based on a received shared uplink pilot signal from the first WD and/or the second WD. Yet further, the RNN determines a beamforming vector for the estimated combined channel; and transmits the signal to the first WD, wherein the signal comprises first data and the possible second data, which first data is decodable only by the first WD.

A phase ambiguity processing method and device are provided. The phase ambiguity processing method includes: deciding symbols on a Y polarization state and an X polarization state of a received signal, and mapping to obtain first bit information, where the received signal includes a plurality of first signals; checking and analyzing the first bit information to generate a first check result; judging the first check result to obtain a judgment result as to whether the received signal has phase ambiguity; acquiring at least one of the plurality of first signals in the received signal when the judgment result indicates that the received signal has phase ambiguity; performing phase rotation on the first signal to obtain a second signal; and checking and analyzing the second signal, storing the second signal so that the first signal is replaced with the second signal for decoding processing if a check result is normal.

The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data rate beyond a 4G communication system such as LTE. According to an embodiment of the present invention, a method for transmitting a synchronization signal by a base station in a filter bank multi carrier (FBMC) system and a base station using the same may be provided, the method comprising the steps of: generating a frequency-domain quadrature amplitude modulation (QAM) symbol sequence having a length of k for a synchronization signal; mapping the QAM symbol sequence to a sub-carrier of a filter bank on the basis of the correlation characteristic of the synchronization signal; generating a quadrature amplitude modulation-filter bank multicarrier (QAM-FBMC) symbol including the synchronization signal on the basis of the mapping, and transmitting the generated QAM-FBMC symbol. In addition, a terminal communicating with the base station and an operation method for the terminal may be provided.

A method of auto-detection of WLAN packets includes selecting a first Golay sequence from a first pair of Golay complementary sequences associated with first packet type, each Golay sequence of the first pair of Golay complementary sequences being zero correlation zone (ZCZ) sequences with each Golay sequence of a second pair of Golay complementary sequences associated with a second packet type, and transmitting a wireless packet carrying a short training field (STF) that includes one or more instances of the first Golay sequence.

The present invention provides a method for hybrid scanning to reduce overhead in a beam scanning scheme in a millimeter wave (mmWave) system, and devices supporting same. The method for hybrid scanning in a wireless access system supporting millimeter wave technology, according to one embodiment of the present invention, comprises the steps of: receiving a synchronization signal to synchronize with a base station; synchronizing with the base station using the synchronization signal; receiving, from the base station, first pilot signals having different configuration patterns according to each transmitting antenna; ray-scanning using the first pilot signals; selecting a candidate beamforming port set through the ray-scanning; generating second pilot signals having different configuration patterns according to each beamforming port included in the candidate beamforming port set; and transmitting, to the base station, the second pilot signals to perform beam scanning with the base station.