Adaptive channel quality estimation algorithm to support link adaptation

Abstract

RF communications received by a wireless terminal from a servicing base station are used to determine the channel quality such as reported bit error probability (BEP). The RF communications may be in the form of RF bursts that are part of a data frame. An estimated BEP may be determined from the signal to noise ratio (SNR) of the RF bursts and or a sequence of soft decisions extracted from the RF bursts, and their historical performance. The SNR maps to an estimated BEP based upon the modulation format of the RF bursts. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). The reported BEP may be based upon the estimated BEP, RBER, and/or RBER threshold. The RBER threshold may be adaptively incremented or decremented depending upon whether or not the RF communications were properly decoded. The size of the increment or decrement may be based on the channel quality.