Pseudo-omnidirectional base station arrangement

Abstract

A base station comprising an arrangement of several directional antennas whose individual azimuthal beam patterns achieve substantially omnidirectional coverage is disclosed. The invention is particularly suitable to telecommunications networks in an initial developmental stage, or to networks deployed in rural areas, both scenarios requiring a low-capacity high-range omnidirectional coverage area. The antennas are generally less conspicuous than a purely omnidirectional antenna achieving the same range, and preferably possess horizontal and vertical polarization ports. In its simplest form, the invention provides a single base station transceiver connected simultaneously to the horizontal polarization port of each antenna. Phase shifters may be inserted in the transmit path for cancellation of nulls in the interference pattern resulting from connection the transceiver to more than one antenna at a time. As capacity demand increases, further transceivers can be added without change to the antenna arrangement. An additional transceiver provides either pseudo-omnidirectional coverage if connected to the vertical polarization port of each antenna or directional coverage if selectively connected to the vertical polarization port of a single antenna. In the latter case, carrier-to-interference information is fed to a beam select module that controls a transmit switch matrix for establishing the selective connection.