The present disclosure relates to a communication method and system for converging a 5.sup.th-Generation (5G) communication system for supporting higher data rates beyond a 4.sup.th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. There may be provided a method for receiving a downlink by a UE that uses narrowband communication and a UE for performing the same, the method comprising the steps of: setting one subcarrier, among narrowband frequency resources assigned to the UE, as a narrowband direct current (DC) subcarrier; receiving a signal regarding the narrowband frequency resources from an eNB; and decoding the received signal on the basis of the narrowband DC subcarrier that has been set.

This invention discloses a multicarrier communication system that includes a transmitter equipment and a receiver equipment. According to a timing scheme, the transmitter equipment processes multiple original symbols for transmission on multiple subcarrier channels, and the receiver equipment processes and detects multiple received symbols from the multiple subcarrier channels. During a time frame of data transmission, the initial three of the original symbols for each of the subcarrier channels are three pilot symbols, forming a preamble. The three preambles of every consecutive three of the subcarrier channels form a preamble unit. All the pilot symbols of the preamble unit are expressed as a 33 matrix. When the center pilot symbol of the preamble unit is normalized to 1 or j (i.e., the imaginary unit), the matrix is $\left[\begin{array}{ccc}-j& -j& -j\\ j& 1& -j\\ -j& j& -j\end{array}\right]\mathrm{or}[\begin{array}{ccc}1& 1& 1\\ -1& j& 1\\ 1& -1& 1\end{array}$

A transmission and reception circuit includes a transmission circuit, a reception circuit, and a signal feedback path. The transmission path includes an output section, a signal generating circuit generating an in-phase component signal and an orthogonal component signal, and a transmission analog baseband circuit configured to perform digital to analog conversion of the generated in-phase component signal and orthogonal component signal. The reception circuit includes an input section, a reception analog baseband circuit performing analog to digital conversion of the transmitted in-phase component signal and orthogonal component signal, and a signal detection circuit that detects the analog-to-digital converted in-phase component signal and orthogonal component signal converted by the reception analog baseband circuit. The signal feedback path has a first end which is connected to the output section of the transmission circuit, and a second end which is connected to the input section of the reception circuit.

This invention discloses a multicarrier communication system that includes a transmitter equipment and a receiver equipment. According to a timing scheme, the transmitter equipment processes multiple original symbols for transmission on multiple subcarrier channels, and the receiver equipment processes and detects multiple received symbols from the multiple subcarrier channels. During a time frame of data transmission, the initial three of the original symbols for each of the subcarrier channels are three pilot symbols, forming a preamble. The three preambles of every consecutive three of the subcarrier channels form a preamble unit. All the pilot symbols of the preamble unit are expressed as a 33 matrix. When the center pilot symbol of the preamble unit is normalized to 1 or j (i.e., the imaginary unit), the matrix is

[00001]$\left[\begin{array}{ccc}-j& -j& -j\\ j& 1& -j\\ -j& j& -j\end{array}\right].Math..Math.\mathrm{or}.Math.\left[\begin{array}{ccc}1& 1& 1\\ -1& j& 1\\ 1& -1& 1\end{array}\right].$

A channel estimation method for the multicarrier communication system is also disclosed.

The present disclosure relates to a communication method and system for converging a 5.sup.th-Generation (5G) communication system for supporting higher data rates beyond a 4.sup.th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services.

There may be provided a method for receiving a downlink by a UE that uses narrowband communication and a UE for performing the same, the method comprising the steps of: setting one subcarrier, among narrowband frequency resources assigned to the UE, as a narrowband direct current (DC) subcarrier; receiving a signal regarding the narrowband frequency resources from an eNB; and decoding the received signal on the basis of the narrowband DC subcarrier that has been set.

A transmission circuit includes a transmission signal generation unit, a control unit, and a transmission signal amplification unit. The transmission signal generation unit generates a transmission signal that has been modulated. The transmission signal amplification unit includes a power amplifier that amplifies the transmission signal. The control unit determines a supply voltage signal having an amplitude characteristic of a period identical to that of an envelope of the transmission signal and supplies the supply voltage signal to the power amplifier. The control unit determines an output timing of the supply voltage signal such that a phase difference between a phase of the envelope of the transmission signal and a phase of the supply voltage signal does not become zero.

A transmission and reception circuit includes a transmission circuit, a reception circuit, and a signal feedback path. The transmission path includes an output section, a signal generating circuit generating an in-phase component signal and an orthogonal component signal, and a transmission analog baseband circuit configured to perform digital to analog conversion of the generated in-phase component signal and orthogonal component signal. The reception circuit includes an input section, a reception analog baseband circuit performing analog to digital conversion of the transmitted in-phase component signal and orthogonal component signal, and a signal detection circuit that detects the analog-to-digital converted in-phase component signal and orthogonal component signal converted by the reception analog baseband circuit. The signal feedback path has a first end which is connected to the output section of the transmission circuit, and a second end which is connected to the input section of the reception circuit.

Methods and apparatuses are provided in which a processor of a transceiver selects one of a real component of a complex signal and an imaginary component of the complex signal. The complex signal has IQ imbalance. An adaptive filter of the transceiver performs a real multiplication operation using an adaptive filter coefficient and the one of the real component and the imaginary component of the complex signal to generate a complex compensation signal. An adder of the transceiver sums the complex signal and the complex compensation signal to generate a compensated signal in which the IQ imbalance is corrected. The compensated signal is output for digital processing.

A device, a method, a mobile station and a non-transitory computer-readable digital storage medium are provided. The device comprises a quadrant classification unit to classify a plurality of symbols in an input shared channel signal into a plurality of quadrants in a complex plane, an energy determination unit to determine a real part energy and an imaginary part energy for the plurality of symbols in each of the plurality of quadrants respectively, an energy summing unit to determine a real part energy sum E.sub.I and an imaginary part energy sum E.sub.Q by summing the real part energy and the imaginary part energy for the plurality of quadrants respectively, and an estimation unit to estimate a SubChannel Power Imbalance Ratio (SCPIR) of the input shared channel signal the real part energy sum E.sub.I and the imaginary part energy sum E.sub.Q.

An apparatus for switching between receivers according to a characteristic of a received signal in a communication system includes a radio frequency unit that modulates at least two signals received from transmission devices, and a Channel Impulse Response (CIR) shape comparison unit that determines characteristics of the modulated signals by using a CIR and selects a receiver according to the determined characteristics of the modulated signals.