FRAME ERROR RATES FOR CONVOLUTIONAL-CODES ON FADING CHANNELS AND THE CONCEPT OF EFFECTIVE E-B N-0/

Estimation of Viterbi decoder performance over channels with time-vary ing received signal levels is the subject of this paper. This work is motivated by a desire to obtain good estimates of the frame error rate (FER) for convolutional codes with bit-level interleaving over fading channels subject to practical power control algorithms. The convoluti onal code performance is quantified through the FER and effective E-b/ N-0, where the latter is defined as the E-b/N-0 on an additive white G aussian noise (AWGN) channel that results in the same FER. Given a rec eived vector of (time-varying) E-b/N-0 values, we compute analytic est imates for the probability of frame error and the effective E-b/N-0 fo r a Viterbi decoder and interleaver combination. In particular, we val idate our analysis using the R = 1/3 convolutional code and interleave r used on the IS-95 CDMA reverse channel. Comparisons with simulations show that even for E-b/N-0 vectors with very large variations, our pr oposed estimates are good to within 0.2 dB for the effective E-b/N-0, giving FER estimates within a factor of two-five of the simulations.