We investigate the performance of a differential amplitude pulse-position modulation with return-to-zero coding (DAPPM-RZ) over an indoor optical wireless channel. We compare the performance of DAPPM-RZ(A=2) with DAPPM(A=2), DPPM and DH-PIM. The result shows that, over a non-dispersive channel, DAPPM-RZ yields better power efficiency than DAPPM. It requires about 1.5 dB less transmit power. However, the bandwidth of DAPPM-RZ is double that of DAPPM. Compared to DPPM, the bandwidth of DAPPM-RZ is about the same as that of DPPM but DAPPM-RZ yields less power efficiency. When the number of bits/symbol(M) is above 3, the DAPPM-RZ is superior to DH-PIM_2 in terms of power efficiency but has less bandwidth efficiency. Over a dispersive channel, given the same value of M, DAPPM-RZ outperforms DPPM, DAPPM (without RZ) and DH-PIM₂ when the normalized rms delay spread is high.

Date Published: 11 February 2005
PDF: 9 pages
Proc. SPIE 5625, Optical Transmission, Switching, and Subsystems II, (11 February 2005); doi: 10.1117/12.574785

Published in SPIE Proceedings Vol. 5625:
Optical Transmission, Switching, and Subsystems II
Cedric F. Lam; Wanyi Gu; Norbert Hanik; Kimio Oguchi, Editor(s)