Tighter performance upper bounds for terminated convolutional codes in Rayleigh fading channels

In this paper, we present tighter performance upper bounds for terminated convolutional codes over Rayleigh fading channels with BPSK and QPSK modulation. The performance upper bounds for convolutional codes are generally obtained from the union bound derived from the transfer function. This bound is quite loose for a terminated trellis. In the literature, performance bounds for terminated convolutional codes with BPSK in AWGN environment have been derived using a new weight enumerator obtained from a modified trellis diagram. In this work, we use the modified trellis approach to derive the weight enumerators for rate 1/2 terminated convolutional codes with QPSK modulation and derive tighter upper bounds using that.