Method and apparatus for dual demodulation of mobile channel signals

A method of receiving mobile radio signals in a communications system and recovering information comprising the steps of:

• (a) receiving a mobile radio signal having information phase modulated on a radio signal carrier;
• (b) demodulating the phase modulated mobile radio signal using coherent demodulation;
• (c) demodulating the phase modulated mobile radio signal received in step (a) using non-coherent demodulation, wherein both the non-coherent demodulation and said coherent demodulation of step (b) are preformed in parallel;
• (d) measuring the quality of data for each signal demodulated in step (b) and step (c);
• and
• (e) selecting, as an output, the data produced by the demodulating step providing the better quality signal.

A method of receiving mobile radio signals in a communications system and recovering information comprising the steps of:

• (a) receiving a mobile radio signal having information phase modulated on a radio signal carrier;
• (b) demodulating the phase modulated mobile radio signal using non-coherent demodulation to provide a first demodulated signal;
• (c) determining the quality of said first demodulated signal;
• (d) comparing the quality of said first demodulated signal to a predetermined signal quality;
• (e) outputting said first demodulated signal if said comparing step indicates that the quality of said first demodulation signal is acceptable;
• (f) if said comparing step does not indicate an acceptable result, demodulating the phase modulated mobile radio signal received in step (a) using coherent demodulation to provide a second demodulated signal;
• (g) determining the quality of said second demodulated signal;
• (h) comparing the quality of said second demodulated signal to the quality of said first demodulated signal;
• and
• (i) selecting as an output the signal with the better quality.

A method of receiving mobile radio signals in a communications system and recovering information comprising the steps of:

• (a) receiving a mobile radio signal having information phase modulated on a radio signal carrier;
• (b) demodulating the phase modulated mobile radio signal using a first demodulation technique to provide a first demodulated signal;
• (c) obtaining a measure of quality of said first demodulated signal;
• (d) outputting said first demodulated signal if said measure of quality of said first demodulated signal satisfies a predetermined criterion;
• (e) if said measure of quality of said first demodulated signal does not satisfy said predetermined criterion, demodulating the phase modulated mobile radio signal received in step (a) using a second demodulation technique to provide a second demodulated signal, one of said first and second demodulation techniques being a coherent demodulation technique and the other of said first and second demodulation techniques being a non-coherent demodulation technique;
• (f) obtaining a measure of quality of said second demodulated signal;
• and
• (g) selecting as an output, the demodulated signal with the better signal quality.

A method of receiving mobile radio signals in a communications system and recovering information, the information including an error detection and correction code, comprising the steps of:

• (a) receiving a mobile radio signal having information phase modulated on a radio signal carrier;
• (b) demodulating the phase modulated mobile radio signal using coherent demodulation;
• (c) demodulating the phase modulated mobile radio signal received in step (a) using non-coherent demodulation, both the non-coherent demodulation and the coherent demodulation of step (b) being performed serially;
• and
• (d) comparing the demodulated signals produced by step (b) and step (c) to determine whether at least one of the demodulated signals has no uncorrectable errors, wherein
• if only one of the demodulated signals has no uncorrectable errors, outputting the one demodulated signal with no uncorrectable errors after correction of all correctable errors, and
• if both of the demodulated signals have no uncorrectable errors, then
• (1) selecting one of the demodulated signal having no uncorrectable errors based on a predetermined criterion, and
• (2) outputting the selected demodulated signal with no uncorrectable errors after correction of all correctable errors.

A method of receiving mobile radio signals in a communications system and recovering information comprising the steps of:

• (a) receiving a mobile radio signal having information phase modulated on a radio signal carrier;
• (b) demodulating the phase modulated mobile radio signal using coherent demodulation;
• (c) demodulating the phase modulated mobile radio signal received in step (a) using non-coherent demodulation, wherein both the non-coherent demodulation and coherent demodulation of step (b) are performed in parallel;
• (d) comparing the demodulated signals obtained from step (b) and step (c) to determine whether at least one of the demodulated signals has no uncorrectable errors, wherein
• if only one of the demodulated signals has no uncorrectable errors, outputting the one demodulated signal with no uncorrectable errors after correction of all correctable errors, and
• if both of the demodulated signals have no uncorrectable errors, then
• (1) selecting one of the demodulated signal having no uncorrectable errors based on a predetermined criterion, and
• (2) outputting the selected demodulated signal with no uncorrectable errors after correction of all correctable errors.