Optimization method of the combination of reception signals in radio receivers in space diversity on the basis of the frequency of FEC impulses generated by the demodulator

摘要

It is described a method capable of conferring an additional optimization opportunity to the strategies commonly applied to combiners in space diversity. radio receivers . The method processes the FEC (Forward Error Correction) impulses generated by the demodulator to obtain a VFEC voltage indicating the frequency of said impulses in a time window of duration equal to the settling time of the receiver. The above enables to monitor the VFEC value, in parallel to the usual combination method, and compare it with a high VFEC in threshold corresponding to a BER value considered critical and barely remediable with the usual method. The surpassing of the critical threshold by the VFEC value causes the switching to a new combination strategy having the purpose to minimize VFEC values to bring them under the critical threshold, in order to be able to return to the original combination strategy valid under the threshold. Also in parallel to the usual combination method, two prediction algorithms are made,: a first one gives a preferential phase shifting direction to be used in case of synchronization loss of the demodulator, situation highlighted by a VFEC value that maintains constant at a full scale value, while a second algorithm gives a first absolute value of phase shifting to be used on the moment of switching to the new combination strategy (Figure 1). <IMAGE>