Motorola Corporation

Soodesh Buljore

Nicholas William Whinnett

Sandrine Vialle

Robert Mark Harrison

Kevin M Laird

David Myara

A method of closed-loop multi-stream wireless communication between a transmitter () comprising a transmit antenna array of N transmit antenna elements and a receiver () comprising a receive antenna array () of M receive antenna elements, wherein a plurality of distinct data steams (xX) are transmitted from the transmit antenna array to the receive antenna array and the data streams are weighted by respective complex weighting matrices before being applied to the transit antenna array. The distinct data steams are separated and estimated at the receiver. The distinct data streams (xxG) are applied to respective sub-groups () of the transmit antenna elements at least one of which comprises a plurality of the transmit antenna elements each of the sub-groups comprising at least Nd transmit antenna elements, where M is greater than or equal to (N/Nd). The complex weighting matrices (vto vn) are functions of the respective transmission channels (hij) of the data streams (x, to xG) including the respective sub-groupes of transmit antenna elements. Nd is preferably greater than or equal to two. Each of the complex weighting matrices is calculated to be substantially equal to the eigenvector corresponding to the largest eigenvalue of the matrix H H, where H is the matrix of the equivalent channel including the respective sub-groups of transmit antenna elements () seen by the corresponding data stream HH is the Hermitian transform of the matrix H. The number of the transmit antenna elements in each of the sub-groups is preferably re-configurable during operation as a function of channel conditions.

Wireless communication using multi-transmit multi-receive antenna arrays

Closed loop wireless communication of signals using an adaptive transmit antenna array, in which multiple copies of signals to be transmitted by the transmit antenna array are produced with delays and weights that are functions of the multi-path transmission channel characteristics from the transmit antenna array to a receive antenna array of a receiver and are combined before transmission by the transmit antenna array. The delays and weights of the transmit copies for each transmit antenna element are functions of the respective multi-path transmission channel characteristics from that transmit antenna element to the receive antenna array such that the multi-path signal components propagated to each receiver element are received with distinguishable delays according to the propagation path. The receiver combines the received signal components from each receive antenna element with delays and weights that are respective functions of the multi-path transmission channels.

Wireless transmission using an adaptive transmit antenna array

A transmitter uses adaptive array weights to modify a gain and a phase of a communication signal to produce a plurality of element communication signals coupled to antenna elements in an adaptive array antenna. The communication signal is transmitted along with an element pilot signal that is coupled to one of the elements in the adaptive array antenna. In a receiver, the communication signal is received, and the element pilot signal is received. Thereafter, the adaptive array weights used at the transmitter are estimated in response to comparing characteristics of the received element pilot signal to characteristics of the received communication signal.

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Gif-sur-Yvette, France

Soodesh Buljore