EVALUATION OF THE EXACT UNION BOUND FOR TRELLIS-CODED MODULATIONS OVER FADING CHANNELS

An analytical technique is presented for computing the exact union bou nd on the average bit error probability of trellis coded modulation sc hemes over Rayleigh, Rician, or shadowed Rician;fading channels. To th is end, an integral expression is derived for the pairwise error event probability (PEP), Existing bounds can be obtained as special cases o f this expression, It turns out that a Gauss-Chebysev quadrature rule offers excellent accuracy for this integral. By extension, the exact u nion bound (i.e., the weighted sum of all exact PEP's of a code) can r eadily be evaluated, This method has the same complexity as the union- Chernoff bound, and a few examples are given to show its application.