ANTENNA DIVERSITY ARRANGEMENT IN FREQUENCY HOPPING SYSTEM

摘要

An antenna diversity arrangement is applicable to frequency hopping receiver (34) for receiving data packets transmitted on frequency channels lying within an overall frequency bandwidth, divided into a plurality of sub-bands. In each sub-band the frequency characteristics of the channel will be substantially the same. The choice of antenna (10, 12) for a particular sub-band is done by carrying-out frequency diversity measurements and the selection is treated as being valid for a period of time which may be preset or determined dynamically. In operation the hopping sequence is known to the receiver so that it can determine in advance the frequency of the next data packet to be received and can select the particular antenna without the necessity of carrying out diversity measurements. At the end of the time period the suitability of the selected antenna is checked and if necessary the selection is updated in the receiver.