Commissariat a L'energie Atomique

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Claire Guyon

Mathieu Bouvier Des Noes

Dimitri Ktenas

Julien Barletta

A method for soft demapping of complex-valued symbols y(k) (k=1, 2, . . . , K) by calculation of a Logarithm of Likelihood Ratio (LogLR) such that: wherein bI,q is the qcoded bit of an in-phase part of a transmitted signal, &#x3b2; is an asymptotic Signal-to-Interference-plus-Noise Ratio, {tilde over (y)}(k) is a standardized symbol associated with y(k), &#x3bb; is a reference symbol of QAM constellation associated with a M-QAM modulation, SI,q and SI,q are complex plane partitions that bring together, respectively, all reference symbols &#x3bb; having a '1' at the position (I, q) and all reference symbols &#x3bb; having a '0' at the position (I, q), a formula similar to LogLR being given for the bit bQ,p, pcoded bit of a quadrature part of the transmitted signal. The method applies to code division multiple access transmission systems.

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La Tronche, France

Claire Guyon