Bell Telephone Laboratories

Lucent Technologies Inc.

American Telephone and Telegraph, Co.

Ta-Shing Chu

Michael J Gans

Giovanni Vannucci

Corrado Pietro Dragone

Yu S Yeh

Anthony Acampora

Peter Frank Driessen

Lawrence Joel Greenstein

Robert S Roman

Vinko Erceg

Martin V Clark

Anthony Joseph Rustako, Jr

Robert W England

For use in a wireless network having geographically-distributed base stations that serve wireless terminals, a system for, and method of, improving an operation of the wireless network. In one embodiment, the system includes: (1) a signal quality determination circuit that determines a relative quality of signals communicated between one of the wireless terminals and a set of base stations within range of the one of the wireless terminals and (2) a base station selection circuit, coupled to the signal quality determination circuit, that selects a base station in the set to serve the one of the wireless terminals based on the relative quality of signals.

System and method for optimizing a wireless network by adaptive configuration of base stations and wireless terminals

A wireless communications system includes a number of clusters of repeaters wherein all repeaters within a cluster arc connected to a common hub via respective millimeter-wave radio links. Wireless signals received by the repeaters from end-user devices are transparently carried by the millimeter-wave radio links to respective hubs that act as concentrators for the repeaters. The hubs may be linked to a wireless network base station (in an outdoor setting) or alternatively to a server or a PBX (in an indoor environment) via a high-speed transmission facility, such as a fiber optic cable that is thus shared by all the repeaters.

Method and system for connecting cells and microcells in a wireless

A terrestrial radio system which utilizes spot beams, time division multiple access and frequency reuse to provide communications services from a base station to remote customers within a system service region. The base station advantageously is arranged with multistage switching so as to permit the respective sharing of radio transmitters and receivers over larger number of antenna transmitting and receiving ports.

Terrestrial communications system

The present invention relates to a dual frequency band, dual-mode feedhorn comprising three serially connected waveguide sections (20, 22, 24) and a separate discontinuity (21, 23) at each joint between waveguide sections. More particularly, the feedhorn comprises a first waveguide section (20) for supporting the TE.sub.11 mode in both frequency bands. A first discontinuity (21) symmetrically increases the first waveguide size for converting a portion of the TE.sub.11 mode in both frequency bands into the TM.sub.11 mode. The second waveguide section (22) connected to the first discontinuity comprises an aperture size for supporting the TE.sub.11 mode in both frequency bands but only the TM.sub.11 mode of the higher frequency band. A second discontinuity (23) symmetrically increases the size of the second waveguide for converting another portion of the TE.sub.11 mode in both frequency bands into the TM.sub.11 mode. A third waveguide section (24) coupled to the second discontinuity is capable of propagating both modes in both frequency bands with a length to cause the vector sums of each of the remaining TE.sub.11 and TM.sub.11 modes in each frequency band to be in phase at the exit port of the feedhorn.

Small dual frequency band, dual-mode feedhorn

The present invention relates to a feed arrangement for use with compact scanning beam antennas which comprises a linear phased array of small feed elements (10) which form an approximate line source that radiates a wedge-shaped cylindrical beam toward a subreflector (12) which is shaped to focus the wedge-shaped cylindrical beam to a point source which then produces a spherical wavefront. The spherical wavefront can then be focused by a main reflector (14) into linear scanning beams if desired. Multiple linear phased arrays of small feed elements can be disposed parallel to each other to form a multibeam feed arrangement for producing multiple fixed or scanning spot beams.

Compact scanning beam antenna feed arrangement

The present invention relates to an antenna arrangement capable of correcting for astigmatism over a broadband range, the antenna arrangement comprising a main focusing reflector arrangement (10), such as, for example, a Cassegrain antenna system, a feed (12) and astigmatic correction means (14) disposed between the feed and the main focusing antenna arrangement. The astimatic correction means comprises a first and a second doubly curved subreflector (16, 18) or lens (30, 32) which are curved in orthogonal planes to permit the launching of an astigmatic beam of constant size and shape over a broadband range.

Broadband astigmatic feed arrangement for an antenna

The polarization properties of the field radiated from a polarization grid have been found to be similar to those in the aperture of an offset curved focusing reflector. Therefore, broadband cancellation of the polarization rotation in a large offset reflector is substantially accomplished in the present invention by the opposite prerotation of the incident feed radiation via a polarization grid. For maximum cancellation the polarization grid, having parallel spaced-apart elements, is disposed at an angle to a plane normal to the feed axis of the offset reflector which approximates one-half of the value of the angle between the feed axis and the offset reflector axis.

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Lincroft, NJ, United States of America

Ta-Shing Chu