Raytheon Company

Ramaiah Velidi

Ronald L Meyer

William P Golemon

The present invention relates to a transmit diversity antenna system employing active antenna electronics (with both receive and transmit amplifiers distributed among the elements of the antenna), polarization diversity on receive, and polarity diversity along with time delay diversity on transmit. The combination of these three techniques, in wireless communications applications, improves the efficiency and performance of both the transmitted and received signals at a base station, as well as the received signal at the mobile. In practice the present invention enables a substantially &ldquo;balanced link&rdquo; to exist between the base station and a mobile.

Wireless communications system

Dynamic antenna pattern modification is accomplished with multi-element, multi-column antennas having the radiation pattern controlled dynamically based on the number of users serviced by the sectors of a multi-sector base station. The number of users is determined either directly through information available from the base station, or indirectly by monitoring the system load (number of users). Sectors of the cell servicing fewer users are expanded to accommodate users from portions of an adjacent sector, in the same cell, by modification of the antenna coverage patterns in each sector. The antenna pattern for a sector serving a relatively large number of users, for a given cell radius, would contract in azimuth for both transmit and receive functions and decrease both transmitted output power and received signal sensitivity. Simultaneously, antenna coverage patterns in the adjacent sector (in the same cell) would expand in azimuth to provide the same cell radius, coverage and performance level as prior to the pattern modification.

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Plano, TX, United States of America

Ramaiah Velidi