This paper proposes a novel coding and transmis-sion scheme for satellite image broadcasting to a large number of receivers. First, the proposed scheme employs a hybrid 3D transform; it first applies a 1D low-complexity Karhunen-Loève transform (KLT) that used a clustering approach as spectral decorrelating transform, and then followed by 2D discrete cosine transform (DCT) to remove redundant information within a spatial band. Second, the transmission power is directly allocated to the data according to their distributions and magnitudes without forward error correction (FEC). Third, these data are transformed by Hadamard matrix and transmitted over a dense constellation. The proposed scheme supports approximately the best quality to multiple users with diverse channel conditions without FEC and modulation. Experiments on satellite images demonstrate that the proposed scheme improves the average image quality by 2.49 dB, 3.52 dB, and 4.20 dB over LineCast, SoftCast-3D, and Softcast-2D, respectively, and it achieves up to 7.33 dB gain over JPEG2000 with FEC.
|
