Title :
BER performance of M-ary PPM free-space optical communications with channel fading
Author :
Abaza, Mohammed R. ; Mohammed, Nazmi A. ; Aly, Mostafa H.
Author_Institution :
Dept. of Electron. & Commun, Arab Acad. for Sci., Technol. & Maritime Transp, Cairo, Egypt
Abstract :
In this paper, we have shown the advantage of using 4-ary pulse position modulation (PPM) using intensity modulation with direct detection (IM/DD) as a power efficient system over coherent differential phase shift keying (DPSK) as a bandwidth efficient system in free space optical (FSO) weak turbulence channel (log-normal channel) and strong turbulence channel (negative-exponential channel). The comparison is done using avalanche photodetector (APD) and PIN receivers. A correct expression is derived for DPSK in negative-exponential channel using APD. The performance of 4-ary PPM is enhanced using high order 256-PPM modulation and forward error correction (FEC). We employed standard Reed-Solomon RS (255,239) and RS (255,223). This work was further extended by exploiting concatenated Reed-Solomon codes, RS (255,239) as an outer code and RS (255,223) as an inner code for higher efficiency.
Keywords :
Reed-Solomon codes; differential phase shift keying; error statistics; fading channels; forward error correction; optical modulation; optical receivers; photodetectors; pulse position modulation; telecommunication channels; 4-ary pulse position modulation; APD receivers; BER performance; DPSK; FEC; FSO weak turbulence channel; IM-DD; M-ary PPM free-space optical communications; PIN receivers; avalanche photodetector receiver; concatenated Reed-Solomon codes; differential phase shift keying; fading channel; forward error correction; free space optical weak turbulence channel; high order 256-PPM modulation; intensity modulation with direct detection; negative-exponential channel; power efficient system; Adaptive optics; Bit error rate; Optical computing; Optical modulation; Optical receivers; Optical refraction; Presses; Free space optical (FSO); M-ary pulse position modulation (M-ary PPM); PIN photodiode; atmospheric turbulence channel; avalanche photodiode (APD); concatenated Reed-Solomon (CRS) codes; differential phase shift keying (DPSK);
Conference_Titel :
High Capacity Optical Networks and Enabling Technologies (HONET), 2011
Conference_Location :
Riyadh
Print_ISBN :
978-1-4577-1170-1
DOI :
10.1109/HONET.2011.6149799
