Koninklijke Philips Corporation N.v.

St-Ericsson Sa

Ipg Electronics 503 Limited

Richard J Caldwell

David Hillary Evans

Adrian W Payne

Kevin Robert Boyle

Robert Fifield

An antenna diversity receiver has a low-IF receiving mode and a diversity selection mode, and a switch arrangement for coupling one of the antennas to the IF channels when in the receiving mode, and coupling each of the channels to a different one of the antennas in the selection mode. A diversity controller compares qualities of signals received simultaneously from the different antennas during the selection mode, and controls the switch arrangement in the receiving mode, to use the better antenna. The quality measurement is carried out during reception of a carrier before a preamble to a desired signal is received, so that there is more time to obtain a better signal quality measurement and to enable better averaging over time. The channels have a polyphase filter with switchable cross coupling between the channels, so that it acts as two independent low pass filters in the selection mode.

Low-if pre-preamble antenna diversity receiver

A method of protecting an apparatus from radio frequency interference, comprises a policing terminal (PT) detecting the presence of an interfering radio terminal () in the protected environment and actively rendering ineffective or terminating transmissions by the interfering radio terminal. Various options can be followed by the policing terminal (PT) including (a) attempting to become the master station of a network of which the interfering terminal is a member and instructing the members to close down or (b) failing to become the master station and transmitting interference signals for at least a selected portion, for example preamble and sync, of the duration of a data packet transmitted by the interfering station.

Method of, and apparatus for, protecting from radio frequency interference

In a radio communication system comprising a plurality of stations () operating in a peer-to-peer mode, each station stores information relating to the transmission parameters of other stations. Such information may include the frequency offset and received signal strength of signals from the other stations. One station acts as central controller and allocates time slots for transmission from a first station () to a second station (). Before the first station () receives a signal from the second station () it makes initial adjustments to its receiver circuitry depending on the stored information about previous signals received from that station (). This simplifies the task of adjusting the receiver circuitry during the preamble of the signal transmitted by the second station ().

Radio communication system

An antenna diversity system includes at least two antennas. Each antenna may be connected via a common connection point to a receiver by a respective switch which presents a low impedance connection between the antenna and receiver in the on state and a substantially reactive load to the antenna in the off state. Selection of appropriate impedances for the off state load enables the antennas to function as an array with a variety of beam patterns depending on the state of the switches. Cycling through a sequence of switch states steers the antenna beam providing improved resistance to fading and multipath effects. Alternatively, the antennas may be connected to a hybrid coupler, which enables two beam patterns to be available simultaneously for signal quality measurement and comparison.

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Reigate, United Kingdom

Richard J Caldwell