The proposed solution relates to a method and an apparatus in a communication system. The solution includes receiving as an input a frame including of a set of data symbols and reference symbols, each data symbol forming a rectangular symbol constellation of samples, derotating the first symbol of the set on the basis of the reference symbols, and setting phase rotating angle of the first symbol as zero. The solution further includes for each following successive symbol in the set of symbols: performing equalization; reducing the number of samples in the constellation by selecting samples in two or more corners of the constellation by utilizing two or more threshold values; estimating the phase rotating angle of the symbol from the reduced number of samples and derotating the symbol on the basis of the determined phase rotating angle.

Methods, systems, and devices for wireless communication are described. A transmitting device may transmit a wakeup message to another device. The wakeup message may be transmitted using a transmit diversity scheme in accordance with aspects of the present disclosure. The transmit diversity may, for example, include a cyclic shift diversity scheme, a phase rotation scheme, a symbol generation scheme, or combinations thereof. The transmit diversity may in some cases improve a communication range of the wakeup message or otherwise benefit the wireless communications system.

A wireless communication device includes a radio frequency antenna and a transceiver. The transceiver includes a receiver having a switching architecture configured to generate a plurality of output phases within a local oscillator period based on the filtered RF signal and a respective plurality of local oscillator signals. The plurality of output phases can be organized into at least K groups where K is an integer of four or greater, and each nth group of the K groups includes nth and (n+K)th output phases of the plurality of output phases. The receiver can difference the nth and (n+K)th output phases of each respective group of the K groups, resulting in gain-added output phases.

A wireless communication system includes an RF reception unit configured to receive a radio signal from a terminal; a channel estimation unit configured to estimate channel information of a wireless transmission path with respect to the terminal; a demodulation unit configured to perform soft decision demodulation on the radio signal; a quantization unit configured to quantize a log likelihood ratio obtained through soft decision demodulation in the demodulation unit, on the basis of a statistical distribution determined using an average value of the log likelihood ratio determined in accordance with a modulation scheme used in wireless communication with the terminal and a variance of a log likelihood ratio obtained on the basis of the channel information; and a decoding unit configured to perform a decoding process on the log likelihood ratio quantized by the quantization unit.

A wireless communication system includes an RF reception unit configured to receive a radio signal from a terminal; a channel estimation unit configured to estimate channel information of a wireless transmission path with respect to the terminal; a demodulation unit configured to perform soft decision demodulation on the radio signal; a quantization unit configured to quantize a log likelihood ratio obtained through soft decision demodulation in the demodulation unit, on the basis of a statistical distribution determined using an average value of the log likelihood ratio determined in accordance with a modulation scheme used in wireless communication with the terminal and a variance of a log likelihood ratio obtained on the basis of the channel information; and a decoding unit configured to perform a decoding process on the log likelihood ratio quantized by the quantization unit.

Methods, systems, and apparatus for EM communications. One of the apparatus includes a super-regenerative amplifier (SRA) configured to receive a binary phase shift keying (BPSK) modulated signal and to output an amplitude signal as a function of changes in phase in the BPSK modulated signal; a pseudo synchronous demodulator that rectifies the amplitude signal and generates an envelope of the rectified amplitude signal; and an analog to digital converter that converts the amplitude values of the envelope to digital binary values.

A non-coherent communication system in which a transmitting device does not transmit a pilot/DMRS, such that the receiving device may be configured to determine or decode the information received from the transmitting device without performing any channel estimation. An apparatus for wireless communication at a receiving device receives, from a transmitting device, a non-coherent signal having data. The apparatus may determine data from the received signal without performing a channel estimation. In another aspect, an apparatus at a transmitting device divides an information payload including a set of bits into multiple subsets of bits, maps each of the multiple subsets of bits into a respective sequence of complex symbols, generates a non-coherent transmission signal based on the respective sequences, and transmits the non-coherent transmission signal to a receiving device.

A non-coherent communication system in which a transmitting device does not transmit a pilot/DMRS, such that the receiving device may be configured to determine or decode the information received from the transmitting device without performing any channel estimation. An apparatus for wireless communication at a receiving device receives, from a transmitting device, a non-coherent signal having data. The apparatus may determine data from the received signal without performing a channel estimation. In another aspect, an apparatus at a transmitting device divides an information payload including a set of bits into multiple subsets of bits, maps each of the multiple subsets of bits into a respective sequence of complex symbols, generates a non-coherent transmission signal based on the respective sequences, and transmits the non-coherent transmission signal to a receiving device.

Methods, systems, and devices for wireless communications are described. A method of wireless communication is described. A user equipment (UE) may receive an indication of one or more filter coefficients used by a base station to filter a reference signal used by the UE to determine channel quality information (CQI). The UE may receive a reference signal from the base station, and may determine the CQI based on the received reference signal and the one or more filter coefficients. The UE may transmit the determined CQI to the base station.

A user equipment (910) is provided for use in a cellular network. The user equipment includes a transceiver (1010), a processor (1020), and a memory (1030). The user equipment (910) is configured to determine, for a data transmission, a mapping form a demodulation reference signal (DMRS) to a PNT-RS. A DMRS resulting signal is generated from a subset of DMRS for a first resource element in a subcarrier. The DMRS resulting signal is copied from the first resource element to a second resource element assigned to the PNT-RS in the subcarrier. The data transmission is transmitted using the DMRS resulting signal and the PNT-RS.