Methods, systems, and devices for wireless communications are described that provide a repeater for beamforming a received signal at a millimeter wave (mmW) radio frequency via one or more scan angles or beamforming directions and then retransmitting and beamforming the signal at the mmW radio frequency. Repeaters may include analog and digital components for downconverting on the received signal to reduce a frequency of the signal from the mmW frequency to an intermediate frequency (IF) or baseband frequency, and then filtering the downconverted signal to reduce interference. The filtering may include digital filtering or a combination of analog and digital filtering, in which a set of filter coefficients for the digital filtering is selected based on beamforming parameters used to receive the signal, retransmit the signal, or both. The repeater may then upconvert the filtered signal back to the mmW frequency for the retransmission of the signal.

An equalizer can connect with N receiving antennas that receive single carrier transmission signals transmitted from M transmitting antenna(s) in the same frequency band at the same time, and receives as input L signals sampled in a sampling period T from each of the N receiving antennas, the equalizer comprising, a first selection part that selects K signal(s) from the L signals for each of the N receiving antennas as signals to be multiplied by a first tap coefficient(s), and a second selection part selects L-K signal(s) to be multiplied by a second tap coefficient(s), from the L signals obtained by multiplying signals in the same sampling period for each of the N receiving antennas by the tap coefficient(s) and performing addition thereof.

A method for decreasing multi-path interference, for a vehicle radio receiver including at least two radio reception antennas that each receive a plurality of radio signals composed of time-shifted radio signals resulting from a multi-path effect. The plurality of radio signals combined to deliver a combined radio signal y.sub.s to be played, with: y.sub.n=W.sub.n.sup.T[G.sub.1,n.sup.S, X.sub.1,n+G.sub.2,n.sup.S, X.sub.2,n] at time n, where x.sub.1 and x.sub.2 are vectors the components of which correspond to the plurality of signals received by the first antenna and by the second antenna, respectively, G.sub.1,n.sup.S and G.sub.2,n.sup.S are scalars the components of which are the complex weights of a spatial filter and w.sub.n.sup.T is the transpose matrix of a vector the components of which are the complex weights of a temporal filter. The method includes implementation of an iterative adaptation algorithm to determine the complex weights of the spatial filter and the complex weights of the temporal filter.

Disclosed are an IQ mismatch compensation method and apparatus for a radio frequency communication system, a compensation device and a communication device. The method comprises: acquiring an interaction result of test signals between a transmitting component and a receiving component; obtaining angle mismatch parameters of a pre-determined type according to the interaction result; determining a frequency domain compensator for performing mismatch compensation on the frequency-dependent angle mismatch parameters according to the following formulae: Y(w)=X(w)jP(w)*X*(w) and Y(w)=X(w)+jP(w)*X*(w); and performing frequency domain compensation on the frequency-dependent angle mismatch parameters by using the frequency domain compensator. Also disclosed is a computer storage medium.

A method for decreasing multi-path interference, for a vehicle radio receiver including at least two radio reception antennas that each receive a plurality of radio signals composed of time-shifted radio signals resulting from a multi-path effect. The plurality of radio signals combined to deliver a combined radio signal y.sub.s to be played, with: y.sub.n=W.sub.n.sup.T[G.sub.1,n.sup.S, X.sub.1,n+G.sub.2,n.sup.S, X.sub.2,n ] at time n, where x.sub.1 and x.sub.2 are vectors the components of which correspond to the plurality of signals received by the first antenna and by the second antenna, respectively, G.sub.1,n.sup.S and G.sub.2,n.sup.S are scalars the components of which are the complex weights of a spatial filter and w.sub.n.sup.T is the transpose matrix of a vector the components of which are the complex weights of a temporal filter. The method includes implementation of an iterative adaptation algorithm to determine the complex weights of the spatial filter and the complex weights of the temporal filter.

A computer-implemented method, performed in a network node, for estimating one or more relative channel gains and one or more channel phases associated with a wireless propagation channel (H) between N transmit antennas (220) and M receive antennas (230) in a line-of-sight, LOS, multiple-input multiple-output, MIMO, communication system (200), the method comprising configuring a channel equalizer to compensate for differences in complex gain over the wireless propagation channel (H) between the N transmit antennas (220) and the M receive antennas (230), configuring a phase tracker to compensate for differences in phase between a set of transmit side oscillators (240) at the N transmit antennas (220) and a set of receive side oscillators (250) at the M receive antennas (230), obtaining a set of equalizer coefficients (W) from the channel equalizer indicative of relative complex gain differences of propagation paths between the N transmit antennas (220) and the M receive antennas (230), obtaining a set of phase compensation values (E) from the phase tracker representing estimated phases of the set of transmit side oscillators and the set of differences of propagation paths between the N transmit antennas (220) and the M receive antennas (230), obtaining a set of phase compensation values (E) from the phase tracker representing estimated phases of the set of transmit side oscillators and the set of

.[.An equal gain composite beamforming technique which includes the constraint that the power of the signal output by each antenna is the same, and is equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. By reducing output power requirements for each power amplifier, the silicon area of the power amplifiers are reduced by as much as N times (where N is equal to the number of transmit antennas) relative to a non-equal gain composite beamforming technique..]. .Iadd.A method and apparatus are disclosed for a transmission technique by a wireless communications device which includes providing that the power applied to each transmit antenna may be equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. The device may determine a total transmit power and produce a multi-carrier signal for transmission. Accordingly, the device may apply a power to each of the N transmit antennas, for the multicarrier signal, which is equal to the total transmit power divided by N. Further, the device may produce a weight for each of the N transmit antennas used. The device may weight the multi-carrier signal for each antenna per the produced weight. Each transmit antenna signal may be amplified by an amplifier coupled to that antenna..Iaddend.

A radio receiver is disclosed, comprising: a receiving stage configured to receive a multi-layered signal comprising a plurality of layers; a division stage configured to divide the plurality of layers into a first subset and a second subset; a first whitening filter configured to filter the multi-layered signal based on a noise and interference covariance measure derived from the second subset to provide a first filtered multi-layered signal; and a first detection stage configured to detect at least one layer of the first subset based on the first filtered multi-layered signal.

A method of generating a transmission signal and a MIMO transmitter are disclosed. The method includes the steps of selecting a reference RE from an RE group including a plurality of resource elements (REs), generating a common precoder and a preprocessing filter to be shared by the plurality of the REs belonging to the RE group based on channel information of the reference RE, generating first signals corresponding to a precoding signal for each of the plurality of the REs in a manner of applying the common precoder to transmission data of each of the plurality of the REs and generating second signals in a manner of compensating first signals of REs except the reference RE among the plurality of the REs using channel information of each of plurality of the REs and the preprocessing filter.

In one embodiment, an apparatus includes: a first radio receiver to receive and downconvert a first radio frequency (RF) signal to a first digital signal; a second radio receiver to receive and downconvert a second RF signal to a second digital signal; a correlation circuit to receive the first and second digital signals and determine a correlation between the first and second digital signals; a weight calculation circuit to determine a first weight value and a second weight value based at least in part on the correlation; and a combiner circuit to combine the first and second digital signals according to the first and second weight values.