Documentation

lteRIDecode

Rank indication channel decoding

Syntax

Description

example

out = lteRIDecode(chs,in) performs the block decoding on soft input data, in. The input is assumed to be encoded using the procedure defined for RI in TS 36.212 [1], Section 5.2.2.6 for given channel transmission configuration, chs. The function returns the decoded output, out, as a vector of length ORI, the number of uncoded RI bits transmitted.

The block decoding will be performed separately on each soft input data using a maximum likelihood (ML) approach, assuming that in has been demodulated and equalized to best restore the originally transmitted values.

The RI decoder performs different type of block decoding depending upon the number of uncoded RI bits to be recovered. For ORI less than 3 bits, the decoder assumed the bits are encoded using the procedure defined in TS 36.212 [1], Section 5.2.2.6. For decoding 3 to 11 RI bits, the decoder assumes the bits are block encoded using the procedure defined in TS 36.212 [1], Section 5.2.2.6.4. For decoding greater than 11 bits, the decoder performs the inverse procedure described in TS 36.212 [1], Section 5.2.2.6.5.

Examples

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Decode RI Bits for 64QAM

Decode coded rank indication (RI) soft input bits for a 64QAM channel transmission configuration.

Generate rank indication bits and initialize the channel transmission configuration structure. Enocde logical RI bits and turn logical bits into 'LLR' data. Decode the RI bits.

ri = [1;0;1];
chs.Modulation = '64QAM';
chs.QdRI = 1;
chs.ORI = length(ri);
chs.NLayers = 1;
codedRI = lteRIEncode(chs,ri);
codedRI(codedRI == 0) = -1
codedRI =

    1
   -1
    1
   -1
   -1
    1

decRI = lteRIDecode(chs, codedRI)
decRI =

     1
     0
     1

Input Arguments

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chs — Channel transmission configurationstructure

Channel transmission configuration, specified as a structure. Multiple codewords can be parameterized by two different forms of the chs structure. Each codeword can be defined by separate elements of a 1-by-2 structure array, or the codeword parameters can be combined together in the fields of a single scalar, or 1-by-1, structure. Any scalar field values apply to both codewords and a scalar NLayers is the total number. See UL-SCH Parameterization for further details.

Modulation — Modulation format'QPSK' | '16QAM' | '64QAM' | cell array of strings

Modulation scheme type, specified as a string or cell array of strings. If there are two blocks and you provide a cell array with two strings, each string is associated with a transport block.

Data Types: char | cell

ORI — Number of uncoded RI bits0 (default) | optional | nonnegative integer

Number of uncoded RI bits, specified as a nonnegative integer. The RI decoder performs different type of block decoding depending upon the number of uncoded RI bits to be recovered.

For ORI less than 3 bits, the decoder assumed the bits are encoded using the procedure defined in TS 36.212 [1], Section 5.2.2.6.

For decoding 3 to 11 RI bits, the decoder assumes the bits are block encoded using the procedure defined in TS 36.212 [1], Section 5.2.2.6.4. For decoding greater than 11 bits, the decoder performs the inverse procedure described in TS 36.212 [1], Section 5.2.2.6.5.

Data Types: double

NLayers — Number of transmission layers1 (default) | optional | 2 | 3 | 4

Number of transmission layers, specified as 1, 2, 3, or 4.

Data Types: double

Data Types: struct

in — RI input bitsnumeric vector | cell array of numeric vectors

RI input bits, specified as a numeric vector or a cell array of numeric vectors. The block decoding will be performed separately on each soft input data using a maximum likelihood (ML) approach assuming that in has been demodulated and equalized to best restore the originally transmitted values.

Data Types: double | cell

Output Arguments

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out — Decoded outputlogical column vector

Decoded output, returned as a logical column vector. The vector length is determined by the value of ORI.

Data Types: logical

References

[1] 3GPP TS 36.212. "Multiplexing and channel coding." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.

Introduced in R2014a

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