Apparatuses, methods, and systems for precoding multi-carrier signals are disclosed. One method includes obtaining a transmission channel matrix between a terminal and a plurality of separate users, wherein the transmission channel matrix includes channel estimates for a plurality of subcarriers of the multi-carrier signal, wherein the terminal is one of a plurality of terminals interfaced with a central processing unit, and wherein the terminal communicates with the plurality of spatially separate user with the multi-carrier signals. The method further comprises determining a precoding for the terminal based on a distribution of user signal power across the transmission channel between the terminal and the plurality of spatially separate user, and determining a precoding for the central processing unit based on the precoding for the terminal and based on the transmission channel matrix, wherein a precoding matrix for the central processing unit is multi-carrier signal dependent.

A communication device is provided that includes a baseband circuit and a transmitter configured to transmit a first signal and a projected signal. The baseband circuit is configured to determine the projected signal based on an estimated signal state information such that an energy of a shaped projected signal is smaller than an energy of a shaped signal. The estimated signal state information is an estimate of a signal state information based on the first signal and a received signal that is received by a receiver of the second communication device. The shaped projected signal is the projected signal received by the receiver of the second communication device and filtered by a filter of the second communication device. The shaped signal is the received signal filtered by the filter of the second communication device.

Embodiments of the invention provide a decoder for decoding a signal received through a transmission channel in a communication system, said signal comprising a vector of information symbols, said transmission channel being represented by an upper triangular matrix, wherein the decoder comprises: a processing unit (309) configured to determine a set of division parameters depending on at least one division metric derived from components of said upper triangular matrix; a decoding unit (311) configured to divide said upper triangular matrix into two or more sub-matrices using said set of division parameters in accordance with a division of said vector of information symbols into two or more sub-vectors, and to determine at least one estimate of each sub-vector of information symbols by applying a symbol estimation algorithm,
wherein the decoder is configured to determine at least one estimate of said vector of information symbols from the estimates of said sub-vectors of information symbols.

What is disclosed is a method for wireless communication comprising receiving a wireless communication via a receiver of the mobile communication device, deriving a demodulation reference signal from a first plurality of symbols of the wireless communication; creating a channel estimation matrix using the demodulation reference signal; inverting the channel estimation matrix to obtain a channel pseudo-inverse matrix; deriving a tracking reference signal from a second plurality of symbols of the wireless communication; calculating a phase shift for one or more additional symbols based on the tracking reference signal; determining a corrected channel pseudo-inverse matrix for the one or more additional symbols by adjusting the channel pseudo-inverse matrix according to the calculated phase shift; and controlling the receiver to accomplish data detection using the corrected channel pseudo-inverse matrix on one or more orthogonal frequency division multiplexing subcarriers.

The present disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4.sup.th-Generation (4G) communication system such as Long Term Evolution (LTE). According to various embodiments, in a multiple-input multiple-output wireless communication system, a receiving apparatus may include at least one processor and at least one transceiver. The at least one transceiver may be configured to receive a signal including a plurality of symbols, perform Successive Interference Cancellation (SIC) related to a first symbol of the plurality of symbols on the received signal to obtain a processed signal, determine symbol-sums by applying an equalization matrix for integer forcing to the processed signal, and determine information words corresponding to the plurality of symbols based on the symbol-sums.

What is disclosed is a method for wireless communication comprising receiving a wireless communication via a receiver of the mobile communication device, deriving a demodulation reference signal from a first plurality of symbols of the wireless communication; creating a channel estimation matrix using the demodulation reference signal; inverting the channel estimation matrix to obtain a channel pseudo-inverse matrix; deriving a tracking reference signal from a second plurality of symbols of the wireless communication; calculating a phase shift for one or more additional symbols based on the tracking reference signal; determining a corrected channel pseudo-inverse matrix for the one or more additional symbols by adjusting the channel pseudo-inverse matrix according to the calculated phase shift; and controlling the receiver to accomplish data detection using the corrected channel pseudo-inverse matrix on one or more orthogonal frequency division multiplexing subcarriers.

A method and apparatus for transmitting using beam are disclosed. A wireless transmit/receive unit (WTRU) may transmit a first physical random access channel (PRACH) preamble to a base station using a first beam at a first power level. The WTRU may receive an indication that the first PRACH preamble was received by the base station. If the indication was received, the WTRU may transmit data. If the indication was not received, the WTRU may select the first beam or a second beam to use for a second PRACH preamble. Further, the first and second beams may be different beams. If the first beam is selected, the WTRU may increase a transmission power level of the second PRACH preamble by a first power ramp step. If the second beam is selected, the WTRU may not increase the transmission power level of the second PRACH preamble by the first power ramp step.

The present invention discloses an adaptive parameter adjustment method for a hybrid precoding millimeter-wave transmission system. The method includes the following step: interacting between a transmitter and a receiver for a number of radio frequency chains that need to be established. The receiver calculates, according to a received signal power at the time of established a different number of radio frequency chains and a total power consumption at the time of established the different number of radio frequency chains, the number of the radio frequency chains that need to be established. According to the present invention, under a condition of balancing power consumption and a rate, a number of radio frequency chains that need to be established is adaptively selected, so as to optimally configure power consumption and a transmission rate in a millimeter-wave transmission system.

An apparatus for controlling an equalizer is provided. The apparatus comprises interface circuitry configured to receive at least one of an input signal and an output signal of the equalizer. The apparatus further comprises processing circuitry configured to determine at least one signal metric based on the at least one of the input signal and the output signal of the equalizer, select an operating mode of the equalizer from a plurality of different operating modes based on the determined signal metric, and control the equalizer to operate in the selected operating mode.

The present disclosure includes an ML (Maximum Likelihood) detector. An embodiment of the ML detector comprises a search value selecting circuit and an ML detecting circuit. The search value selecting circuit is configured to select a search value according to a communication index and a modulation type or determine the search value according to a predetermined value, in which the communication index is related to a reception signal or a derivative thereof, the search value is associated with a search range, and a number of candidate signal value(s) in the search range is not greater than a number of all candidate signal values of the modulation type. The ML detecting circuit is configured to execute an ML calculation according to the search value and one of the reception signal and the derivative thereof, so as to calculate a log likelihood ratio of every candidate signal value in the search range.