# lteACKDecode

HARQ-ACK channel decoding

## Description

`[`

performs block decoding on soft input data `out`

,`blkerr`

] = lteACKDecode(`chs`

,`in`

)`in`

, assumed to be
encoded using the procedure defined for HARQ-ACK in Section 5.2.2.6 of [1], for PUSCH channel transmission configuration
`chs`

. The decoded output, `out`

, is a
vector of length `OACK`

, the number of uncoded HARQ-ACK bits
transmitted.

**Note**

If `NBundled`

is 0, TDD ACK-NACK descrambling is
disabled.

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 `chs.NLayers`

is the total number. See UL-SCH Parameterization for
further details.

The block decoding is performed separately on each soft input
data codeword using a maximum likelihood (ML) approach, assuming that `in`

has
been demodulated and equalized to best restore the originally transmitted
values.

The HARQ-ACK decoder performs different types of block decoding depending upon the number of
uncoded HARQ-ACK bits to be recovered (`OACK`

). For
`OACK`

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

For decoding between 3 and 11 HARQ-ACK 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 between 12 and 22 bits, the decoder performs the inverse procedure described in TS 36.212 [1], Section 5.2.2.6.5. For decoding more than 22 bits, the decoder performs rate-matching, tail-biting Viterbi decoding, and 8-bits CRC decoding, which is the inverse procedure described in Section 5.2.2.6.

## Examples

## Input Arguments

## Output Arguments

## References

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

## Version History

**Introduced in R2014a**

## See Also

`lteACKEncode`

| `lteRIDecode`

| `lteCQIDecode`

| `lteULSCHDeinterleave`

| `lteULSCHDecode`

| `lteUCIDecode`