Apparatus, and associated method, for operating upon received data at a receiving station capable of diversity operation
View Patent ↗Apparatus, and an associated method, for a receiving station, such as the receive part of a mobile station, that has diversity antennas. The receiving station includes both legacy demodulators and a diversity demodulator. Calculations are made to determine signal indicia associated with the signal energy detected at the diversity antennas. Responsive to the signal indicia, selection is made as to whether to utilize demodulation data, demodulated pursuant to a diversity demodulation technique or pursuant to a legacy demodulation technique. As the characteristics of received signals change, reselection of the demodulation is correspondingly made, such as on a frame-by-frame basis of frame-formatted data.
1. Apparatus for a receiving station that contains a first diversity antenna and a second diversity antenna, said apparatus comprising:
a first receive signal operator adapted to receive a first signal associated with first signal energy detected at the first diversity antenna;
the first receive signal operator further adapted to receive a second signal associated with second signal energy detected at the second diversity antenna;
the first receive signal operator configured to operate upon a combination of the first and second signals, to ascertain a first attribute thereof; and
a selector adapted to receive a first indication of the first attribute ascertained by said first receive signal operator, said selector configured to select which of: 1) diversity demodulation result of a combination of the first and second signal energy or 2) a demodulation result of the first signal energy or 3) a demodulation result of the second signal energy is to be used at the receiving station based upon the first indication of the first attribute.
2. The apparatus of claim 1 wherein the first receive signal operator operates on the first and second signals prior to demodulation of at least one of the first and second signals.
3. The apparatus of claim 1 further comprising:
a second receive signal operator adapted to receive the first signal and the second signal;
the second receive signal operator configured to operate upon a combination of the first and second signals to ascertain a second attribute thereof; and
the selector is further adapted to receive a second indication of the second attribute, the selector is further configured to select which of: 1) a diversity demodulation result of a combination of the first and second signal energy or 2) a demodulation result of the first signal energy or 3) a demodulation result of the second signal energy are to be used at the receiving station based upon the first indication of the first attribute and the second indication of the second attribute.
4. The apparatus of claim 1 wherein the first attribute comprises a correlation value identifying correlation between the first signal energy and the second signal energy.
5. The apparatus of claim 1 wherein the first attribute ascertained by said receive signal operator comprises an amplitude difference value identifying a difference between amplitudes of the first signal energy and the second signal energy.
6. The apparatus of claim 3 wherein the first attribute comprises a correlation value identifying correlation between the first signal energy and the second signal energy, and the second attribute comprises an amplitude difference value identifying a difference between amplitudes of the first signal energy and the second signal energy.
7. The apparatus of claim 1 further comprising a diversity demodulator adapted to receive the first signal energy and the second signal energy, said diversity demodulator configured to demodulate the combination of the first and second signal energy.
8. The apparatus of claim 1 further comprising a first legacy demodulator adapted to receive the first signal energy and a second legacy demodulator adapted to receive the second signal energy, said first legacy demodulator and said second legacy demodulator configured separately to demodulate the first signal energy and the second signal energy, respectively, applied thereto.
9. The apparatus of claim 1 wherein the first signal energy and the second signal energy comprises frame-formatted data, and wherein selection made by said selector is successively made upon selected successive ones of frames of the frame-formatted data.
10. A method for operating a receiving station that has a first diversity antenna and a second diversity antenna, said method comprising:
ascertaining a first attribute associated with a combination of a first signal energy detected at the first diversity antenna and a second signal energy detected at the second diversity antenna; and
selecting, which of: 1) a diversity demodulation result of a combination of the first and second signal energy or 2) a demodulation result of the first signal energy or 3) a demodulation result of the second signal energy is to be used at the receiving station based upon a first indication of the first attribute.
11. The method of claim 10 wherein the first signal energy and the second signal energy comprise frame-formatted data and wherein said operations of ascertaining, and selecting are iteratively made upon selected successive ones of frames of the frame-formatted data.
12. The method of claim 10 wherein said operation of ascertaining comprises ascertaining an individual quality metric associated with at least one of the first signal energy and the second signal energy and ascertaining a combined quality metric associated with a combination of the first and second signal energy.
13. The method of claim 12 wherein selection made during said operation of selecting further comprises determining which quality metric is of a most appropriate quality.
14. The method of claim 10 further comprising the operation of demodulating subsequent to said operation of selecting.
15. The method of claim 10 further comprising:
ascertaining a second attribute associated with the combination of the first signal energy and the second signal energy; and
the selecting operation is based upon the first indication of the first attribute and a second indication of the second attribute.
16. An apparatus for selecting demodulated data from a plurality of demodulators comprising:
a first demodulator adapted to demodulate a first signal detected at a first antenna resulting in a first demodulated signal;
a second demodulator adapted to demodulate a second signal detected at a second antenna resulting in a second demodulated signal;
a third demodulator adapted to demodulate a third signal, the third signal is a combination of the first signal and the second signal resulting a third demodulated signal;
a quality metric calculator connected with the first, second and third demodulators, the quality metric calculator adapted to calculate a first quality metric for the first demodulate signal, a second quality metric for the second demodulated signal, and a third quality metric for the third demodulated signal; and
a signal quality evaluation module connected with the quality metric calculator, the signal quality evaluation module adapted to receive the first, second and third quality metrics and to select a demodulated signal from one of the three demodulated signals based upon the first, second and third quality metrics.
17. The apparatus of claim 16 wherein the quality metric is selected from a group consisting of: BER (Bit Error Rate), a BLER (Block Error Rate), an FER (Frame Error Rate), an SNR (Signal-to-Noise) ratio, a C/I (Carrier to Interference Ratio), a SINR (Signal-to-Interference plus Noise ratio), an associated E b /N 0 .
18. A method for selecting demodulated data from a plurality of demodulators comprising:
demodulating a first signal detected at a first antenna resulting in a first demodulated signal;
demodulating a second signal detected at a second antenna resulting in a second demodulated signal;
demodulating a third signal, the third signal is a combination of the first and second signal, resulting in a third demodulated signal;
calculating a first quality metric for the first demodulated signal, a second quality metric for the second demodulated signal, and a third quality metric for the third demodulated signal; and
selecting a demodulated signal from one of the three demodulated signals based upon the first, second and third quality metrics.
19. The method of claim 18 , wherein the quality metric is selected from a group consisting of: BER (Bit Error Rate), a BLER (Block Error Rate), an FER (Frame Error Rate), an SNR (Signal-to-Noise) ratio, a C/I (Carrier to Interference Ratio), a SINR (Signal-to-Interference plus Noise ratio), an associated E b /N 0 .