The present invention relates to a method for transmitting, by a base station, a downlink signal using a plurality of transmission antennas comprises the steps of: applying a precoding matrix indicated by the PMI, received from a terminal, in a codebook to a plurality of layers, and transmitting the precoded signal to the terminal through a plurality of transmission antennas. Among precoding matrices included in the codebook, a precoding matrix for even number transmission layers can be a 2×2 matrix containing four matrices (W1s), the matrix (W1) having rows of a number of transmission antennas and columns of half the number of transmission layers, the first and second columns of the first row in the 2×2 matrix being multiplied by 1, the first column of the second row being multiplied by coefficient “a” of a phase, and the first column of the second row being multiplied by “−a”.

An apparatus for performing fractionally spaced adaptive equalization with non-integer sub-symbol sampling has an adaptive equalizer that receives a continuous stream of input data having a non-integer, fractional delay between consecutive samples at a non-integer, sub-symbol rate and outputs a stream of equalized data based on tap weights of taps of the adaptive equalizer that are spaced at an interval corresponding to the non-integer, sub-symbol rate. The tap weights are updated independently of the fractional delay between consecutive samples of the input data using an error signal. An equalizer output alignment component downstream of the adaptive equalizer aligns the stream of equalized data with a corresponding transmitted symbol.

Embodiments of a passive buffer circuit and a wideband communication circuit that uses the passive buffer circuit are disclosed. In an embodiment, the passive buffer circuit includes buffer elements connected between input terminals and output terminals that are connected to input terminals of a communication component circuit with a plurality of input transistors. Each of the buffer elements provides a first path with a resistor and a second path with a series-connected capacitor and inductor. The passive buffer circuit further includes current sources connected between the output terminals and at least one fixed voltage and a feedback loop from the input transistors to the current sources to control direct current (DC) voltage at each of the input terminals of the communication component circuit. The feedback loop includes an error amplifier that controls the current sources based on voltages on the input transistors with respect to a reference voltage.

Methods and apparatus are provided for calibrating an antenna array in a receiver. A training signal for calibrating the antenna array is injected into a data signal received on each receive path to generate combined signals on each receive path. The combined signals are equalized by respective equalizers. The coefficients of the equalizers are determined by comparing a feedback signal for each receive path with the equalized signal to estimate the impairment on each received path. The estimated impairment on each receive path is used to adapt the equalize coefficients for a respective equalizer to compensate for the impairment. After equalization, an estimate of the observed training signal on each receive path is subtracted from the equalized signal for the same receive path to generate estimates of the received data signals for demodulation and decoding.

The present invention provides a terminal device that allows constraints on user allocation to be prevented and spread codes to be allocated in a scheduler when non-adaptive HARQ is employed using a PHICH. A codeword generator (103) generates code words (CW) by encoding data, a layer mapping unit (108) places each CW in one or a plurality of layers, a DMRS generator (110) generates a reference signal for each layer in which a CW is placed by using any resource among a plurality of resources defined by a mutually orthogonal plurality of OCCs, and an ACK/NACK demodulator (102) receives a response signal indicating a retransmission request. When a response signal requesting retransmission of only a CW placed in a plurality of layers is received, the DMRS generator (110) uses each resource having the same OCC among the plurality of resources for the reference signals generated in the corresponding layers.

Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.

Method and apparatus of primary cell indication for enhanced control channel demodulation method and apparatus are disclosed. Control information receiving method in a multi-distributed node system includes demodulating a first cell identification (ID) based on a synchronization signal (SS), demodulating information indicating a second cell ID based on a radio resource control (RRC) message and demodulating enhanced physical downlink control channel (e-PDCCH) based on the second cell ID, Accordingly, it may be possible to reduce complexity that occurs when the optimal prediction motion vector is induced and to enhance efficiency.

A receiver includes a plurality of equalization modules each configurable to provide a selectable compensation value to a data bit stream received by the receiver, and a control module configured to perform a plurality of back channel adaptations on the data bitstream to achieve a target bit error rate for the receiver, each back channel adaptation being associated with a set of compensation values of the equalization modules, determine a most common set of compensation values derived from the performance of the plurality of back channel adaptations, and determine an optimized set of compensation values based on the most common set of compensation values.

Methods and systems are described for generating a time-varying information signal at an output of a variable gain amplifier (VGA), sampling, using a sampler having a vertical decision threshold associated with a target signal amplitude, the time-varying information signal asynchronously to generate a sequence of decisions from varying sampling instants in sequential signaling intervals, the sequence of decisions comprising (i) positive decisions indicating the time-varying information signal is above the target signal amplitude and (ii) negative decisions indicating the time-varying information signal is below the target signal amplitude, accumulating a ratio of positive decisions to negative decisions, and generating a gain feedback control signal to adjust a gain setting of the VGA responsive to a mismatch of the accumulated ratio with respect to a target ratio.

Described are methods and circuits for margin testing digital receivers. These methods and circuits prevent margins from collapsing in response to erroneously received data and can thus be used in receivers that employ historical data to reduce intersymbol interference (ISI). Some embodiments detect receive errors for input data streams of unknown patterns and can thus be used for in-system margin testing. Such systems can be adapted to dynamically alter system parameters during device operation to maintain adequate margins despite fluctuations in the system noise environment due to e.g. temperature and supply-voltage changes. Also described are methods of plotting and interpreting filtered and unfiltered error data generated by the disclosed methods and circuits. Some embodiments filter error data to facilitate pattern-specific margin testing.