Kabushiki Kaisha Toshiba

Cheran Malsri Vithanage

Yue Wang

Mong Suan Yee

Robert Jan Piechocki

Christophe Andrieu

Determining a beamforming vector for a multi-antenna transmitter commences by determining an eigen-beamformer vector from the channel matrix and, for a number of iterations commencing with the eigen-beamformer vector, rotating the vector into a reference direction in vector space such that application of the rotated vector would result in peak radiation being directed in said reference direction, sampling a radiation pattern associated with the rotated eigen-beamformer vector with respect to transmission direction, compressing resultant samples to reduce spatial directivity induced by the vector, developing a rotated candidate beamformer on the basis of said compressed samples and returning said rotated candidate beamformer to the orientation of said vector before said rotating and storing said resultant vector as a candidate vector. Then, the candidate vectors are compared for the iterations and one is selected for use which best meets one or more selection criteria.

Wireless communications apparatus

This invention generally relates to methods, apparatus and computer program code for decoding signals, and more particularly to trellis-based decoding using a variant of a BCJR procedure. The invention includes a trellis decoder for decoding symbols of a received signal, the symbol including a sequence defined by transitions between states of a trellis, the trellis decoder including: means for performing a forward recursion through the trellis to determine a first set of probabilities (&#x3b1;(X)) each defining a probability of a said trellis state (X) responsive to one or more current or earlier received signal values (y); means for providing a second set of (&#x3b2;(X)) probabilities each defining a probability of one or more received signal values (y) given an earlier the trellis state (X); means to decode the received signal to determine probabilities (p(b|y)) for symbols of a corresponding transmitted sequence of symbols from the first and second sets of probabilities; and where the decoder further includes: means to select states for determining the first set of probabilities responsive to one or more received signal values later than a the trellis state defining a probability in said first set.

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Bristol, United Kingdom

Cheran Malsri Vithanage