| 摘要 |
The present invention relates to improving the time and frequency diversity for rotated QAM constellations when used with and without time-frequency slicing, as well as to corresponding methods, transmitters, and receivers. Specifically, the present invention provides a component interleaver that ensures that components of a constellation block are mapped to different RF channels. This is achieved by writing real and imaginary components of the rotated constellations independently of each other column-by-column into a matrix with N R rows, applying a cyclic shift to each column of the matrix holding the imaginary components, and reading the real and imaginary components row-by-row. The cyclic shifts are selected for each column in accordance with a shift pattern that contains only integers that are not a multiple of N R . Optimum spreading of the components over time can be achieved by configuring the shift pattern such that the average shift equals N R /2. The sequence of components read from the matrix may then be divided into slices, each of which may then be transmitted through a corresponding RF channel. The present invention also provides a component interleaver for D-dimensional rotated constellations that provides an even spreading of the components of each constellation over the FEC block by setting N R =D and shifting each column of the matrix holding the imaginary components by D/2 components. |
