Method and apparatus for determining signal quality

In a receiver that receives a plurality of phase modulated digital symbols, a method for generating bit reliability information of the plurality of phase modulated digital symbols, each phase modulated digital symbol having associated therewith phase information, the method comprising the steps of:

• a) for each digital symbol of at least some of the plurality of phase modulated digital symbols, determining a symbol quality estimation based on the associated phase information;
• b) determining signal quality information of the plurality of phase modulated digital symbols based on a predetermined number of determining symbol quality estimations;
• and
• c) said generating bit reliability information based upon the signal quality information and the phase information.

A circuit for generating bit reliability information for phase modulated digital symbols comprising:

• a phase detector adapted to receive said phase modulated digital symbols for generating a phase estimate for each said phase modulated digital symbol;
• an error determiner coupled to receive said phase estimate, said error determiner generating a phase error signal;
• a signal quality determiner coupled to receive said phase error signal, said signal quality determiner generating a signal quality indicator;
• and
• a bit reliability indicator coupled to receive said signal quality indicator and said phase estimate and generate bit reliability information.