The present specification relates to a reception apparatus and method for demodulating a signal in a wireless AV system. The reception apparatus estimates a transmission signal on the basis of an MMSE weight matrix. The reception apparatus divides the estimated transmission signal for respective reception antennas and performs an IFFT. The reception apparatus estimates and compensates for phase noise for the respective reception antennas on the basis of the signal for which the IFFT has been performed. The reception apparatus demodulates the estimated and compensated signal for respective streams.

This application proposes multi-beam antenna systems using spherical lens are proposed, with high isolation between antenna ports and compatible to 2×2, 4×4, 8×8 MIMO transceivers. Several compact multi-band multi-beam solutions (with wideband operation, 40%+, in each band) are achieved by creating dual-band radiators movable on the track around spherical lens and by placing of lower band radiators between spherical lenses. By using of secondary lens for high band radiators, coupling between low band and high band radiators is reduced. Beam tilt range and side lobe suppression are improved by special selection of phase shift and rotational angle of radiators. Resultantly, a wide beam tilt range (0-40 degree) is realized in proposed multi-beam antenna systems. Each beam can be individually tilted. Based on proposed single- and multi-lens antenna solutions, cell coverage improvements and stadium tribune coverage optimization are also achieved, together with interference reduction.

An OFDM signal transmission apparatus is provided, which includes a mapping unit configured to map first signals into N subcarriers and second signals into M subcarrier(s) to form an OFDM signal, wherein N is larger than M. The first signals are each indicating a same bit of retransmission information and the second signals are each indicating a same bit of information other than retransmission information. The OFDM signal transmission apparatus further includes a transmitting unit configured to transmit the formed OFDM signal.

A transmitting apparatus is disclosed. The transmitting apparatus includes an encoder to perform channel encoding with respect to bits and generate a codeword, an interleaver to interleave the codeword, and a modulator to map the interleaved codeword onto a non-uniform constellation according to a modulation scheme, and the constellation may include constellation points defined based on various tables according to the modulation scheme.

A first radio signal is received that was transmitted from a first antenna at a transmitter and a second radio signal transmitted from a second antenna at the transmitter different from the first antenna. The first radio signal is converted to a first orthogonal frequency division multiplexing (OFDM) frame signal, and the second radio signal is converted to a second OFDM frame signal. The first OFDM frame signal includes a grid of multiple frequency subcarriers and time periods, each time period with the frequency carriers corresponding to a first OFDM symbol such that the first OFDM frame includes first OFDM symbols. A first OFDM symbol is carried on frequency subcarriers during a time period, and the first OFDM frame includes first reference OFDM symbols located at corresponding time-frequency resource elements in the grid. Each resource element is defined by a one of the frequency subcarriers and one of the time periods. The second OFDM frame signal is similar and includes second reference OFDM symbols sharing the same grid of frequency subcarriers and time periods as the first OFDM frame. But the second reference OFDM symbols are located at corresponding time-frequency resource elements in the grid different than the corresponding time-frequency resource elements to which the first reference OFDM signals are located their respective OFDM frame signals. The first and second reference OFDM symbols are used to demodulate the first and second OFDM frame signals.

An apparatus includes a low noise amplifier (LNA) multiplexer configured to receive a plurality of radio frequency (RF) signals at a plurality of input terminals and to combine the plurality of RF signals into a combined RF signal that is output at an output terminal. The LNA multiplexer includes a plurality of input signal paths, and each input signal path is coupleable to a respective input terminal of the plurality of input terminals and is configured to receive a respective RF signal of the plurality of RF signals. The apparatus further includes an LNA demultiplexer configured to receive the combined RF signal at an input port coupled to the output terminal and to distribute the combined RF signal to a plurality of output ports, each output port of the plurality of output ports configured to output the combined RF signal to a respective downconverter of a plurality of downconverters.

Techniques for minimum-mean-square-error (MMSE) channel estimator using channel-dependent composite subcarriers and combined pilots reduce computational complexity and memory usage while still achieving near optimum performance. A set of interpolation filters, that are pre-calculated for different radio propagation environments, e.g., channel state information, are stored in look up tables at the receiver and used to interpolate channel estimates for combined pilots to obtain channel estimates for individual subcarriers.

In one aspect, a method for wireless communication includes transmitting a first message indicating a precoding matrix identifier configured to identify a particular precoding matrix for precoding by another wireless communication device for at least one future transmission; and receiving a second message indicating information about whether the particular precoding matrix was or will be used for the at least one future transmission. In another aspect, a method for wireless communication includes receiving a first message indicating a precoding matrix identifier configured to identify a particular precoding matrix for precoding by the wireless communication device for at least one future transmission; and transmitting a second message indicating information about whether the particular precoding matrix was or will be used for precoding for the at least one future transmission. Other aspects and features are also claimed and described.

An apparatus and method for generating a broadcast signal frame corresponding to a time interleaver supporting a plurality of operation modes are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling time interleaver information corresponding to the time interleaver, the time interleaver uses one of time interleaver groups, and the time interleaver performs the interleaving by using one of a plurality of operation modes.

Methods, systems, and devices for wireless communications are described. A transmitting device (e.g., a user equipment (UE) or base station) may reduce a peak to average power ratio (PAPR) by clipping signals transmitted to a receiving device according to a clipping level. The receiving device may receive, from the transmitting device, an indication of the clipping level associated with a reference signal. The receiving device may receive the reference signal and identify distortions based on the clipping level. The receiving device may iteratively reconstruct peaks of the clipped reference signal until the receiving device is able to obtain accurate pilot symbols for use in channel estimation. The techniques described herein may enable receiving devices to improve efficiency and reliability of communications by improving channel estimation, which may increase the probability of successfully decoding transmitted information.