A method for transmitting a signal by an apparatus having a plurality of antennas in a wireless communication system, according to one embodiment of the present invention, comprises the steps of: mapping complex modulation symbols to L layers; sequentially applying a unit matrix U, a diagonal matrix D, and a precoding matrix W to the symbols which have been mapped to the L layers; and mapping symbols which have been mapped to DMRS ports by applying W, D and U, wherein W is one of M sets of precoders, each of the M sets of precoders comprising a plurality of column vectors, and wherein if the number of DMRS ports is smaller than M*L, the M sets of precoders include at least one identical column vector.

Systems and methods for a communication system including a set of transmitters, wherein operations of the set of transmitters are synchronized with an accuracy bound by a synchronization error. A controller communicatively connected to each transmitter in the set of transmitters, wherein the controller is configured to: determine a tap delay for a communication channel between a receiver and each transmitter in the set of transmitters to produce a set of tap delays. Determine a minimal length of a cyclic prefix as a function of a sum of the synchronization error and a maximal tap delay in the set of tap delays. Finally, controls at least some transmitters in the set of transmitters to transmit a message to the receiver using a cyclic delay diversity (CDD) with the cyclic prefix having at least the minimal length.

Systems, devices, and methods associated with interference aware sounding reference signals are provided. A method for wireless communication includes receiving, at a wireless communication device in communication with a first base station, an interfering signal from a second base station (or other base stations); determining, at the wireless communication device, a spatial direction of the interfering signal; and transmitting, with the wireless communication device, a signal to the first base station based on the spatial direction of the interfering signal. Another method of wireless communication includes receiving, at a first base station, a signal from a wireless communication device, the signal based on a spatial direction of an interfering signal received by the wireless communication device from a second base station (or other base stations); transmitting, with the first base station, a downlink communication to the wireless communication device, the downlink communication beamformed in the spatial direction based on the signal received from the wireless communication device.

A transmission apparatus includes orthogonal frequency division multiplexing (OFDM) modulation signal generating circuitry. The circuitry generates a first OFDM modulation signal by inserting symbols for demodulation in a first plurality of subcarriers at a first time and in a second plurality of sub-carriers at a second time adjacent to the first time, the symbols for demodulation being reception processing reference symbols of a reception apparatus, and, inserting symbols, having both an in-phase (I) component and a quadrature-phase (Q) component in an I-Q plane of zero, in the second plurality of sub-carriers at the first time and in the first plurality of sub-carriers at the second time. The circuitry generates a second OFDM modulation signal by inserting the symbols for demodulation in the second plurality of subcarriers at the first time and in the first plurality of sub-carriers at the second time, and, inserting the symbols, having both the I component and the Q component in the I-Q plane of zero, in the first plurality of sub-carriers at the first time and in the second plurality of sub-carriers at the second time. The apparatus includes transmitting circuitry to transmit the first and the second OFDM modulation signals, from respective different antennas, in an identical frequency band.

Provided are M signal processors that respectively generate modulated signals for M reception apparatuses (where M is an integer equal to 2 or greater), a multiplexing signal processor, and N antenna sections (where N is an integer equal to 1 or greater). When transmitting multiple streams, each of the M signal processors generates two mapped signals, generates first and second precoded signals by precoding the two mapped signals, periodically changes the phase of signal points in the IQ plane with respect to the second precoded signal, outputs the phase-changed signal, and outputs the first precoded signal and the phase-changed second precoded signal as two modulated signals. When transmitting a single stream, each of the M signal processor outputs a single modulated signal. The multiplexing signal processor multiplexes the modulated signals output from the M signal processors, and generates N multiplexed signals. The N antenna sections respectively transmit the N multiplexed signals.

Provided is a method of calibrating a power for a multiple input and multiple output-orthogonal frequency division multiplexing transmitter having a plurality of antennas via a measurement equipment, the method including: receiving a cyclic delay diversity (CDD) signal simultaneously output from the transmitter to obtain a starting point of a frame of a corresponding signal; performing a fast Fourier transform on a sample proceeded from the starting point by an extent of a maximum CDD delay; calculating a channel coefficient; calculating a channel impulse response and a power of the channel impulse response; converting CDD delay values of each antenna into values in units of samples by using a sampling rate in the channel impulse response; mapping a peak point position of the channel impulse response to each antenna using CDD delay sample values; and simultaneously performing a power calibration of each antenna based on each peak point power.

A method for operating a large scale antenna array in a wireless communication system includes receiving one or more signals. The one or more signals include information for beamforming to a plurality of user equipments (UEs) using a full-dimensional multiple-input multiple-output (FD-MIMO) beamforming scheme. The FD-MIMO beamforming scheme includes same time resources and same frequency resources that are co-scheduled to the plurality of UEs. The method further includes identifying a time delay of the one or more signals associated with one or more antenna arrays that are distributed in the large scale antenna array and performing a multi-user (MU) joint beamforming on the one or more signals to one or more UEs.

An analog beamforming transmitter includes: a plurality of beamforming transmission circuits coupled in parallel between a signal input and an array of antenna ports, wherein the signal input is configured to receive an analog complex-valued communication signal having an in-phase and a quadrature component, wherein each antenna port of the array of antenna ports is configured to provide a dual-polarized antenna signal having a first polarization component and a second polarization component, wherein each beamforming transmission circuit is coupled between the signal input and a respective antenna port of the array of antenna ports, wherein each beamforming transmission circuit comprises a first coefficient input for receiving a first analog complex-valued beamforming coefficient a set of first analog complex-valued beamforming coefficients and a second coefficient input for receiving a second analog complex-valued beamforming coefficient of a set of second analog complex-valued beamforming coefficients.

A method for X2 interface communication is disclosed, comprising: at an X2 gateway for communicating with, and coupled to, a first and a second radio access network (RAN), receiving messages from the first RAN according to a first X2 protocol and mapping the received messages to a second X2 protocol for transmission to the second RAN; maintaining state of one of the first RAN or the second RAN at the X2 gateway; executing executable code received at an interpreter at the X2 gateway as part of the received messages; altering the maintained state based on the executed executable code; and receiving and decoding an initial X2 message from the first RAN; identifying specific strings in the initial X2 message; matching the identified specific strings in a database of stored scripts; and performing a transformation on the initial X2 message, the transformation being retrieved from the database for stored scripts, the stored scripts being transformations.

A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.