Methods and devices are described for compensating an effect of aging due to, for example, hot carrier injection, or other device degradation mechanisms affecting a current flow, in an RF amplifier. In one case a replica circuit is used to sense the aging of the RF amplifier and adjust a biasing of the RF amplifier accordingly.

Methods and devices are described for compensating an effect of aging due to, for example, hot carrier injection, or other device degradation mechanisms affecting a current flow, in an RF amplifier. In one case a replica circuit is used to sense the aging of the RF amplifier and adjust a biasing of the RF amplifier accordingly.

Provided is a data transmission method using physical network coding in a relay station. The method may include an operation of receiving a first signal and a second signal from first and the second nodes, respectively, an operation of generating a third signal to which a physical network coding is applied based on the first signal and the second signal, an operation of forming a beam which maximizes a lower effective power between effective power of the first channel between the relay station and the first node and effective power of the second channel between the relay station and the second node, and an operation of transmitting the third signal to the first node and the second node based on the beam.

An antenna alignment method and system, with the system having a first device having N.sub.AT transmit beams and N.sub.AR receive beams. The system has a second device having N.sub.BT transmit beams and N.sub.BR receive beams. The first device transmits a signal to the second device according to a first cycle, and traverses switching of N.sub.AT transmit beams according to a third beam mode. The second device receives a signal from the first device according to the first cycle, and traverses switching of N.sub.BR receive beams according to a fourth beam mode, counts a receive signal power in each first cycle, and obtains a receive signal power corresponding to each receive beam according to the fourth beam mode, to determine that a receive signal power corresponding to an Sth receive beam is the highest, and uses the Sth receive beam as a receive beam.

An antenna alignment method and system, with the system having a first device having N.sub.AT transmit beams and N.sub.AR receive beams. The system has a second device having N.sub.BT transmit beams and N.sub.BR receive beams. The first device transmits a signal to the second device according to a first cycle, and traverses switching of N.sub.AT transmit beams according to a third beam mode. The second device receives a signal from the first device according to the first cycle, and traverses switching of N.sub.BR receive beams according to a fourth beam mode, counts a receive signal power in each first cycle, and obtains a receive signal power corresponding to each receive beam according to the fourth beam mode, to determine that a receive signal power corresponding to an Sth receive beam is the highest, and uses the Sth receive beam as a receive beam.

A method of detecting sequences of multi-level encoded symbols. The multi-level encoded symbols are mapped and modulated with a modulation scheme having a number of constellation points identified by a sequence of bits arranged in at least a first and a second group. The first group is encoded with a first encoding scheme, and the second group is encoded with a second coding scheme, and the multi-level encoded symbols are transmitted by multiple transmitting sources and received as a received vector by multiple receiving elements. A first set of candidate sequences is selected and a first set of probability information is calculated for the first set of candidate sequences. Then the first group of bits of the symbols are decoded. The decoded bits of the first group are re-encoded and used to select a sub-set of constellation points. A second set of candidate sequences is selected based on this sub-set of constellation points and a second set of probability information is calculated for the second set of candidate sequences. Finally, the second group of bits of the symbols are decoded.

The present invention relates to precoding and feedback channel information in wireless communication system. A method includes receiving a first Precoding Matrix Index (PMI) and a second PMI from a terminal; mapping one or two codewords into layers; precoding symbols mapped into the layers using a first precoding matrix derived from the first PMI and a second precoding matrix derived from the second PMI; and transmitting the precoded symbols to the terminal, wherein the reception of the first PMI is less frequent than the reception of the second PMI.

Dynamic, untethered array nodes are frequency, phase, and time aligned/synchronized, and used to focus their transmissions of the same data coherently on a target or in the target's direction, using time reversal or directional beamforming. Information for alignment/synchronization may be sent from a master node of the array to other nodes, over non-RF links, such as optical and acoustic links. Some nodes may be connected directly to the master nodes, while other nodes may be connected to the master node through one or more transit nodes. A transit nodes may operate to (1) terminate the link when the alignment/synchronization information is intended for the node, and (2) pass through the alignment/synchronization information to another node without imposing its local clock properties on the passed through alignment/synchronization information. In this way, an end point node may be aligned/synchronized to the master node without a direct link between the two nodes.

The present invention relates to a method for allocating resources for a transmission of pilot signals of a plurality of terminals (18-23, 24-27) of a cellular multiple-input and multiple-output, MIMO, system. The cellular MIMO system (40) comprises at least a first base station (10) and a second base station (15), wherein each of the first and second base stations (10, 15) has a plurality of antennas (13) and a logic (12) which analyzes pilot signals received from a terminal (18-23, 24-27) at the plurality of antennas (13) to obtain information about radio channel properties between the terminal (18-23, 24-27) and the plurality of antennas (13). According to the method, the first base station (10) determines a first resource (1-3) used for transmission of pilot signals of a first terminal (18-23) and a usage type indicating a usage of the first resource (3). The usage type and information about the first resource (1-3) is transmitted from the first base station (10) to the second base station (15). The second base station allocates based on the usage type and the information about the first resource (1-3) a second resource (2) for a transmission of pilot signals of a second terminal (27) to obtain information about properties of a radio channel between the second terminal (27) and the plurality of antennas (13) of the second base station (15).

Signal interference associated with multi-user multiple-input multiple-output (MIMO) full-duplex wireless communication systems is reduced. In an example, first streams are received by a MIMO base station from uplink user devices based on a first availability of channel matrices and second streams are transmitted to downlink user devices based on a second availability of the channel matrices. A weighted sum of a first data rate for a first linear transceiver matrix and a second data rate of a second linear transceiver matrix is maximized based on the channel matrices, the first streams, and the second streams. The base station generates a first linear transceiver vector used in transmission of the first streams to the base station from the uplink user devices and a second linear transceiver vector used in transmission of the second streams from the base station to the downlink user devices.