In this paper, the performance of convolutional code constraint length for bandwidth efficient transmission over AWGN and Rayleigh fading channels is presented. Using intensive simulation and in terms of BER error floor, we evaluate the performance of binary phase shift keying (BPSK) mapping scheme. In addition, the hardware implementation considerations based on the Digital Signal Processor (DSP) platform of convolutional decoding are discussed. To be more specific, the code constraint length effect on both memory management and clock cycles are considered.