The AGWN model, based on the atmospheric attenuation and turbulence effect is present. In the paper, a robust image
watermark technology is proposed based on extended set partitioning in hierarchical trees algorithm (ESPIHT) and low
density Parity check codes (LDPC). The Watermarking Algorithm is applied in the free space optical communication
(FSO) by Joint Source-Channel Coding (JSCC), and simulated in BPSK modulation over AWGN channel and different
level error correction channel coding. The results of simulation show that the presented algorithm is effective and robust
to common image processing operations and some distortions such as cropping, pinching, pixel-shifting and so on. And
it has strong error correction performance in burst errors and random errors, so it is appropriate for complicated
environment of FSO.
Satellite-ground laser communication system based on Turbo code is put forward and analyzed. Firstly, this paper
analyzes channel character, then simulates the characteristic of the system based on Turbo code. The result shows that
Turbo code can well compensate and conquer all kinds of attenuations and noises. So the bit error rate is reduced. In
addition, anti-jamming ability, stability and reliability are improved.
Free-space laser communication is a research direction in wireless communication domain. The image transmission,
compression coding and storage are ones of most important techniques in the free space laser communication. In order to
improve error resilient capability and transmission efficiency for image transmission over noisy and varying channels in
the free space laser communication (FLSC) , we contrive a joint source and channel coding (JSCC) scheme, in which
extended set partitioning in hierarchical trees (ESPIHT) and rate compatible punctured convolutional code (RCPC) are
used. Specifically, ESPIHT segments an image into different sizes of blocks whilst determining different levels of source
significance; RCPC code is then used to provide unequal error protection for individual blocks. Various simulations
show that this scheme can support robust and efficient image transmission in a very effective way.
Experiments demonstrate that the proposed method can obviously improve the image quality compared to that of the
classical approach of separate source and channel coding. The peak SNR for reconstruction image also has some
improvement. It is an effective fast image compression method.