Rake receiver and related methods

A radio frequency (RF) rake receiver comprising:

• a plurality of diversity receive paths, each diversity receive path comprising a respective downconverter, a fractional interpolator coupled to the downconverter, and a rake receiver despreader coupled to the downconverter, and each rake receiver despreader comprising a plurality of rake fingers arranged in a non-sparse configuration;
• differential detection and log-likelihood ratio (LLR) calculation circuitry coupled to the plurality of rake fingers of the respective rake receiver despreader and configured to generate an LLR output for each rake finger, the differential detection and LLR calculation circuitry comprising
• signal power measurement circuitry coupled to a respective rake finger of the plurality of rake fingers,
• a moving average filter coupled to the signal power measurement circuitry,
• path selection circuitry coupled to the moving average filter and configured to exclude rake finger signal energy below a threshold energy level, and
• a differential detector coupled to the path selection circuitry;
• a tracking loop configured to
• generate a composite timing signal based upon the plurality of rake receiver despreaders and the differential detection and LLR calculation circuitry, and
• provide the composite timing signal to the plurality of diversity receive paths;
• and
• forward error correction (FEC) decoder circuitry configured to perform error correction on data received via the diversity receive paths based upon the LLR output.

A method comprising:

• operating a plurality of diversity receive paths, each diversity receive path comprising a respective rake receiver despreader comprising a plurality of rake fingers;
• operating differential detection and log-likelihood ratio (LLR) calculation circuitry to generate an LLR output for each rake finger wherein the differential detection and LLR calculation circuitry is coupled to the plurality of rake fingers of the respective rake receiver despreader and comprising signal power measurement circuitry coupled to a respective rake finger of the plurality of rake fingers, a moving average filter coupled to the signal power measurement circuitry, path selection circuitry coupled to the moving average filter and configured to exclude rake finger signal energy below a threshold energy level, and a differential detector coupled to the path selection circuitry;
• operating a tracking loop by
• generating a composite timing signal based upon the plurality of rake receiver despreaders and the differential detection and LLR calculation circuitry, and
• providing the composite timing signal to the plurality of diversity receive paths;
• and
• operating forward error correction (FEC) decoder circuitry configured to perform error correction on data received via the diversity receive paths based upon the LLR output.