Nortel Networks Corporation

Northern Telecom Limited

James Edward Dalley

Martin Stevens Smith

Dean Kitchener

Adrian David Smith

Mark Newton

Stephen John McKenna

Sectorisation has been used in cellular communications networks in order to increase capacity without the need for obtaining new cell sites. However, previously, the increase in the number of main antenna beams provided by a base station transceiver has not produced a commensurate increase in capacity. For example, a hex sectored tricellular network is found to provide an increase in capacity by a factor of only 1.6 over a tri sectored tricellular network despite the fact that twice as many antenna beams are provided. A multiple beam antenna arrangement is described where the increase in capacity is commensurate with the increase in the number of antenna beams provided. In one example, a nine sectored tricellular CMDA network is described which comprises a multiple beam antenna arrangement with six antenna elements each provided as columns. The antenna beams may be orthogonal and a 6&times;6 Butler matrix beamformer is used which is advantageously loss less. The beamformers may be arranged back to back to allow sharing of power amplifiers to reduce costs and complexity and the number of cables required is reduced by the particular arrangement of beamformer used.

Multiple beam antenna

Current radio telecommunications cell radius estimation methods can result in spurious and inaccurate results outside regions with well sampled signal measurements. The present invention provides an improved cell radius estimation method using path loss and signal source distance data as well as a method for determining models for use in cell estimation without test data. The methods apply a fixed gradient line fit to the data to obtain cell radius estimates and to determine models for one or more geomorphology classifications. Cell radius estimates determined from the test data and the models can be used for cell distribution planning in network coverage planning applications. The invention provides improved accuracy as well as reduced costs in the network planning stage.

Cell radius estimation method

The present invention provides an auxiliary or side lobe cancelling antenna particularly for horizontally polarised main antennas. The auxiliary antenna arrangement for cancelling side lobe interference from a main antenna comprises a ground plane shaped in a concertina or zig-zag fashion. Dipole pairs are spaced from and arranged perpendicular to the front bends, the dipoles having ends angled towards corresponding ground plane sections. The dipoles are connected anti-phase to provide a radiation pattern approximating an ideal auxiliary antenna mask of the main antennas pattern.

Antenna arrangement

A wireless subscriber terminal having an improved performance is disclosed. The terminal 12 comprises: a quarter wavelength monopole first antenna 14; a folded monopole second antenna; and a ground plane having a surface 18 angled with respect to the horizontal, wherein the ground plane has an axis a quarter of a wavelength long extending from a feed point for the first antenna and is electrically symmetrical about the axis. Mutual coupling effects between the first antenna and the second antenna are reduced. A method of operation is also disclosed.

The present invention relates to antennas. One of the problems which arises during the operation of a linear array antenna with electrical downtilt is that cross-polar radiation currents are generated. These cross-polar radiation currents, if at the same frequency as the operating band of the antenna, interfere with the required gain of the antenna. The present invention provides a solution to cross-polar radiation currents with an antenna assembly comprising first and second apertured ground planes with an antenna probe feed network printed upon a dielectric substrate supported therebetween, the array of radiating elements having different phase input feeds, wherein an outwardly extending ground plane flange extends from one of the apertured ground planes. There is also provided a method of receiving and transmitting signals by means of a layered antenna of this construction.

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Harlow, United Kingdom

James Edward Dalley