Demodulation and symbol to bit conversion
out = lteSymbolDemodulate(in,mod)
out = lteSymbolDemodulate(in,mod,dec)
a column vector containing bits resulting from soft constellation
demodulation of complex values in vector
out = lteSymbolDemodulate(
The demodulation algorithm assumes the vector of received symbols
are normalized to fall on constellation points as defined by
lteSymbolModulate provides an output with
the expected constellation scaling.
in— Input symbols to demodulatenumeric column vector
Input symbols to demodulate, specified as a column vector of complex numeric values. Demodulation is performed assuming the input constellation power normalization in accordance with TS 36.211, Section 7.1 , as follows:
- 0.707i; -0.707 + 0.707i]
Complex Number Support: Yes
mod— Modulation format
Modulation format, specified as a string.
dec— Decision mode
Decision mode, specified as a string.
out— Demodulated output bitsnumeric column vector
Demodulated output bits, returned as a numeric column vector.
This argument contains bits resulting from soft constellation demodulation
of complex values vector,
'Hard' decision mode results in the output
containing the bit sequences corresponding to the closest constellation
points to the input.
'Soft' decision mode results in the output
indicating the bit values using the sign (
+ve for 1). For
mode, the magnitude of the output gives a piecewise linear approximation
to the log likelihood ratio (LLR) of the demodulated bits. The algorithm
used for the LLR approximation is described in .
The returned LLRs are scaled such that for a input signal lying on
the constellation points in the preceding description, the output
values lie on the points with the following magnitudes.
[1 3]/sqrt(10) for
[1 3 5 7]/sqrt(42) for
[1 3 5 7 9 11 13 15]/sqrt(170) for
 Tosato, F., and Bisaglia, P. "Simplified soft-output demapper for binary interleaved COFDM with application to HIPERLAN/2." IEEE International Conference on Communications (ICC) 2002, Vol. 2. pp. 664-668.
 3GPP TS 36.211. "Physical Channels and Modulation." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.