抄録
In this paper, the influence of scintillation and background noise on the optical low-density generator matrix code with binary pulse position modulation (LDGM-BPPM) with the unequal transmission power allocation (UTPA) scheme is investigated. In particular, the bit error rate (BER) performance of LDGM-BPPM with the UTPA scheme is evaluated in the presence of avalanche photodiode (APD) noise. Consequently, the following points are clarified. (1) The BER performance increases steadily in proportion to the background noise. (2) The BER of the UTPA scheme deteriorates gradually with increasing variance of scintillation. (3) The optimum value of the power ratio (optimum R) varies with the amount of background noise and scintillation. (4) The quasioptimum R is 3.1. Thus, the UTPA scheme is effective for optical LDGM-BPPM.