Enhancement of punctured turbo code with UTPA in optical wireless channel

In this paper, the performance of rate r=1/2 punctured turbo code using a technique called Unequal Transmission Power Allocation (UTPA) is studied in optical wireless communication (OWC) with intensity modulation and direct detection (IM/DD). UTPA scheme is applied at the outputs of rate r=1/2 punctured turbo encoder. Different powers are allocated to systematic bit and parity bits keeping the total transmission power fixed. BPPM is used as modulation technique and the system's performance is evaluated through simulation in an optical wireless channel. Obtained results suggest that punctured turbo code combined with UTPA technique is an effective method which leads to better Bit Error Rate (BER) performance in an optical wireless channel. Furthermore, suitable power allocation ratio is located for the given channel condition.