It is possible to compress log likelihood ratios (LLRs) by exploiting the mapping symmetry between bits in the same symbol. For example, two LLRs corresponding to the same dimension of a square Quadrature Amplitude Modulation (QAM) symbol can be compressed into a single compressed LLR that excludes the magnitude bits of one of the LLRs because the magnitude component of LLRs for bits corresponding to the same dimension of a square QAM symbol exhibit a piecewise linear relationship with one another. Similar techniques can be used to exploit piecewise linear relationships between a subset of constellation points in a non-square QAM constellation.
展开▼
