2 research outputs found
Sova-Based Iterative Decoding Of Turbo Coded Ook And Turbo Coded Bppm
Infrared wireless communication and optical communication usually adopt on-off keying (OOK) and pulse position modulation (PPM). In [1] we presented the iterative maximum a posteriori probability (MAP) decoding of Turbo coded OOK and Turbo coded binary PPM (BPPM). In this paper, we present a soft-output Viterbi algorithm (SOVA) based iterative decoding of Turbo coded OOK and Turbo coded BPPM. We show that the BER of both Turbo coded OOK and Turbo coded BPPM are almost identical and improved as the number of iterations is increased
Optical Communication in Space: Challenges and Mitigation Techniques
In recent years, free space optical communication has gained significant
importance owing to its unique features: large bandwidth, license-free
spectrum, high data rate, easy and quick deployability, less power and low mass
requirements. FSO communication uses the optical carrier in the near infrared
band to establish either terrestrial links within the Earth's atmosphere or
inter-satellite or deep space links or ground-to-satellite or
satellite-to-ground links. However, despite the great potential of FSO
communication, its performance is limited by the adverse effects viz.,
absorption, scattering, and turbulence of the atmospheric channel. This paper
presents a comprehensive survey on various challenges faced by FSO
communication system for ground-to-satellite or satellite-to-ground and
inter-satellite links. It also provides details of various performance
mitigation techniques in order to have high link availability and reliability.
The first part of the paper will focus on various types of impairments that
pose a serious challenge to the performance of optical communication system for
ground-to-satellite or satellite-to-ground and inter-satellite links. The
latter part of the paper will provide the reader with an exhaustive review of
various techniques both at physical layer as well as at the other layers i.e.,
link, network or transport layer to combat the adverse effects of the
atmosphere. It also uniquely presents a recently developed technique using
orbital angular momentum for utilizing the high capacity advantage of the
optical carrier in case of space-based and near-Earth optical communication
links. This survey provides the reader with comprehensive details on the use of
space-based optical backhaul links in order to provide high-capacity and
low-cost backhaul solutions.Comment: 41 pages, 13 Figures and 8 Tables. arXiv admin note: substantial text
overlap with arXiv:1506.0483