Selecting Delay Values For a Rake Receiver

摘要

Multipath components of transmitted data symbols are received with individual delays and processed by a RAKE unit having a number of fingers. A delay profile is calculated, and delay values for peaks detected therein are determined. A number of peak delay values (P_{A 1} , P_{A 3} , P_{A 4} , P_{A 5} ) representing the largest peaks for the profile are pre-selected, and for each of them a signal-to-interference ratio for delay values in an interval around the pre-selected peak delay value is calculated. In each interval the delay value having the highest signal-to-interference ratio is selected and provided to the RAKE unit with each selected delay being assigned to a RAKE finger. Hereby the ability to select correct and accurate path delays can be improved also in time critical processes, where filtering of the delay profiles over several frames is not possible, because quite accurate delay values can be provided shortly after wake-up of the receiver.