Predictive power control in a digital diversity receiver

A method in a wireless portable communication device having digital diversity receiver for adjusting a receiver power control loop during a radio frame of a known length, the digital receiver having a first receiver branch and a second receiver branch, the method comprising:

• segmenting the radio frame into first, second, and third intervals;
• for the first interval,
• receiving a first signal through the first receiver branch,
• receiving a second signal through the second receiver branch, the second signal originating from a common original signal as the first signal;
• evaluating a receiver power control parameter based upon the first and second signals;
• compensating the receiver power control parameter with an offset value;
• applying the compensated receiver power control parameter to the receiver power control loop;
• for the second interval immediately following the first interval,
• continuing receiving the first signal through the first receiver branch;
• receiving a third signal through the second receiver branch;
• re-evaluating the receiver power control parameter based upon the first signal;
• applying the re-evaluated receiver power control parameter based upon the first signal to the receiver power control loop;
• for the third interval immediately following the second interval,
• continuing receiving the first signal through the first receiver branch;
• re-receiving the second signal through the second receiver branch;
• re-evaluating the receiver power control parameter based upon the first and second signals;
• and
• applying the re-evaluated receiver power control parameter based upon the first and second signals to the receiver power control loop.

A digital diversity receiver comprising:

• a processor configured to segment a radio frame of a known length into a first interval, a second interval, and a third interval;
• a first receiver branch coupled to the processor, the first receiver branch configured to receive a first signal during the first, second, and third intervals of the radio frame;
• a second receiver branch coupled to the processor, the second receiver branch configured to receive a second signal during the first intervals of the radio frame, the first and second signals originating from a common original signal;
• a power control estimator coupled to the processor and to the first and receiver second receiver branches, the power control estimator configured to generate an estimate power control parameter;
• an offset generator coupled to the processor and to the power control estimator, the offset generator configured to generate an offset value and an offset power control parameter, the offset power control parameter based upon the estimate power control parameter and the offset value;
• a power control parameter comparator coupled to the processor and to the offset generator, the power control parameter comparator configured to compare the offset power control parameter and a target power control parameter;
• and
• a diversity combiner coupled to the processor and to the first and second receiver branches, the diversity combiner configured to generate a log-likelihood ratio of the common transmitted signal based upon at least one of the first and second signals.