PUCCH format 3 transmission UCI decoding
ucibits = lteUCI3Decode(cw,n)
a column vector of decoded UCI bits,
ucibits = lteUCI3Decode(
resulting from decoding the soft bit column vector,
Where the output vector
ucibits is expected to
empty if no HARQ-ACK bits are detected.
The decoder uses a maximum likelihood (ML) approach, assuming
cw has been demodulated using
ltePUCCH3Decode, whose input had already
been equalized to best restore the originally transmitted complex
values. Specifically, this function assumes that
properly scaled to reflect a QPSK constellation (±
sqrt(2)/2 amplitude for real and imaginary parts).
If multiple decoded UCI bit vectors have a likelihood equal to the
ucibits is a matrix where each column
represents one of the equally likely bit vectors. If a minimum likelihood
threshold is not met,
ucibits is empty.
This example shows how to encode and decode an ACK using PUCCH format 3 transmission UCI decoding.
Create a Tx ACK vector. Encode the vector using PUCCH format 3. Convert the logical bits into soft data.
txAck = [1;0;0;1]; cw = lteUCI3Encode(txAck); cw = (double(cw)-0.5)*sqrt(2.0);
Decode the received data using the PUCCH format 3 UCI decoder. Verify that the Rx ACK vector matches the Tx ACK vector.
rxAck = lteUCI3Decode(cw,length(txAck))
rxAck = 4×1 logical array 1 0 0 1
cw— Soft bits to decode
Soft bits to decode, specified as a numeric column vector.
n— Number of bits to return
Number of bits to return, specified as a positive scalar integer from 1 through 22.
ucibits— Concatenated HARQ-ACK bits, periodic CSI bits, and Scheduling Request (SR) bit
Concatenated HARQ-ACK bits, periodic CSI bits, and Scheduling
Request (SR) bit, returned as a logical column vector.
the [a0, a1,
... aN-1] bit
sequence as described in TS 36.212 , Section 18.104.22.168. The number of bits returned, N,
is defined by the input argument
ucibits is empty if no UCI bits are detected.
 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.