Abstract: The invention relates particularly to fixed wireless access networks and provides a cellular communication network which serves directional subscribers while reducing co-frequency interference substantially uniformly across the network. The network comprises a plurality of base stations arranged to form sectored cells using a plurality of carrier frequencies, where sectors carrying common frequencies are directionally mis-aligned and arranged such that the polarization of said frequencies are varied with respect to each other across the network in order to reduce co-frequency interference.

Abstract: A base transceiver station operating a sectorized cell of a cellular radio system operates a plurality of narrow uplink main receive beams, and one or a plurality of uplink diversity received beams. A scanning means scans each of the uplink main receive beams to locate a communications channel on the main uplink beams. A diversity receiver receives a diverse beam signal from the diverse beam(s), which is compared with a beam signal received from a main uplink beam, and the main beam signal from the main beam, or a diverse beam signal from the diversity antenna is selected, depending on the comparative signal to noise ratio and signal strength of the main beam signal and diversity beam signal.

Abstract: A frequency allocation method for allocating carrier frequencies to a plurality of fixed beams in a cellular radio based transceiver station comprises maintaining a reserve pool of carrier frequencies, such that any available carrier frequency can be allocated to any fixed beam at any one time in order to deal with capacity demands from mobile stations within an area covered by a fixed beam. A frequency allocation algorithm operates such as to allow a plurality of transceivers to float anywhere across a plurality of fixed directional beams. More carrier frequencies can be added to a beam to deal with increased mobile station capacity demand. The occupancy of channels on the carrier frequencies is continuously monitored, and the number of carrier frequencies per beam is continuously monitored, with the object of releasing unused carrier frequencies to a reserve pool of carrier frequencies, allowing re-deployment of unused carrier frequencies to other beams where necessary.

Abstract: An antenna beam forming for generating a plurality of broad overlapping radiation beams for a cellular radio application comprises an antenna array having a plurality of individual antenna elements, each individual antenna element connected by a cable to a respective diplexor, each diplexor fed by a multi-channel power amplifier receiving an input from an output port of an eight way Butler matrix. Transmission signals are input to seven input ports of the Butler matrix, and output transmission signals are produced at four of the output ports of the Butler matrix. A remaining four output ports are each terminated with a respective matched load. A 3 dB power loss incurred in the Butler matrix is compensated by provision of a plurality of pre-amplifiers prior to the input ports of the Butler matrix, with the power amplification stage being carried out on the outputs of the Butler matrix. Side lobe suppression is maintained by ensuring phase and amplitude integrity across the output channels.

Abstract: A method of configuring a plurality of directional beams in a cellular radio system having a plurality of antennas each communicating over a corresponding respective cell area by re-arrangement of directional beams using a same or like carrier frequency to each other, so as to be directed away from each other, and by restricting signal loading on beams experiencing worst case interference. Interference between geographically close cells is reduced by the method resulting in an improvement in carrier to interference ratio performance. Carrier frequencies of the inner two beams transmitted by an antenna are exchanged for the inner two beams which are transmitted in substantially the same direction by another antenna. Inner beams experiencing highest interference are restricted so as to operate at below their maximum signal load in order to reduce interference within the network.

Abstract: The present invention relates to a radio communications base station antenna. In a first embodiment, the arrangement comprises a plurality of antennas each capable of forming a separate narrow beam in azimuth, wherein the antennas are positioned such that the beams formed by the antennas overlap and the centre of each beam falls midway between the centre and first null of the adjacent beam to provide a uniform coverage in azimuth. The present invention can be deployed in mobile wireless terminals. The use of downlink beam-forming is proposed for systems such as Digital AMPS (D-AMPS). A downlink beam-former typically consists of a number of narrow beams formed by either multiple narrow beamwidth antennas or an array of elements in conjunction with a fixed beam-former. Signal processing techniques can then be used to select an appropriate beam directed towards the subscriber.