Antenna selection control circuitry

DETAILED DESCRIPTION In a first aspect of the invention there is provided antenna selection apparatus for a receiver selectively operable with a first and a second antenna, comprising measurement means for measuring average received signal quality for respective first and second antennas, and selection means for selecting a first or second antenna for subsequent use based on average received signal quality for the first and second antennas wherein the selection means is biased in favour of the first or second antenna having a predetermined likelihood of receiving subsequent signals having best signal quality.
In a second aspect of the invention there is provided a method for selecting an antenna from a plurality of antennas for a receiver operable with the antennas, comprising measuring average received signal quality for respective antennas, and biasing selection of an antenna for subsequent use in favour of an antenna having a predetermined likelihood of receiving subsequent signals having the best signal quality.
An advantage of the present invention is that antenna diversity performance for a receiver may be improved, since an antenna is selected when it has the greatest chance of receiving the best signal quality.
This reduces the likelihood of having to switch antennas later whilst receiving information, and thereby avoids clicks and other disturbing interferences in received information due to phase changes caused by such switching.
Furthermore, this improvement may be achieved with relatively simple averaging of signals.
Additionally, a change in the typical quality of a received signal from an antenna can be taken into account and diversity biased towards that antenna.
An example of such an instance is when a radio telephone is operated in an in-car mode, and external car mounted antennas are input to the radio telephone.
In such circumstances, since both antennas are external, they typically have the same gain or sensitivity to signals as each other.
If selection was biased towards one of the external car mounted antennas, then possibly higher quality signals received by the other car antenna would not be utilised