Documentation

lteCFIDecode

Control format indicator block decoding

Syntax

Description

example

cfi = lteCFIDecode(ibits) performs the block decoding on soft input data ibits, assumed to be encoded using procedure defined in TS 36.212 [1], Section 5.3.4.1. The output, cfi, is a scalar representing the control format indicator (CFI) value resulted after performing block decoding on input data. Strictly speaking, ibits should be a vector 32 bits long, as per encoded cfi. See the lteCFI function reference for details. However, this function can decode any size segment of encoded data.

The value for CFI can be 1, 2, or 3. This value indicates the time span, in OFDM symbols, of the DCI PDCCH transmission (the control region) in that downlink subframe. For bandwidths in which NDLRB is greater than 10 RB, the span of the DCI in OFDM symbols is the same as the actual CFI value. If NDLRB is less than or equal to 10 RB, the span is CFI+1 symbols.

Examples

collapse all

Decode CFI Block

Decode a noisy 32-element vector that represents the block encoding of the control format indicator (CFI) value.

cw = double(lteCFI(struct('CFI',2)));
noisycw = cw + 0.4*randn(length(cw),1);
cfi = lteCFIDecode(noisycw)
cfi =

           2

Input Arguments

collapse all

ibits — Soft input datanumeric vector

Soft input data, specified as a numeric vector of length 32. This input data is assumed to be encoded using the procedure defined in TS 36.212 [1], Section 5.3.4.1.

Output Arguments

collapse all

cfi — Control format indicator value1 | 2 | 3

Control format indicator value, returned as a positive scalar integer. This integer represents the CFI value resulting from performing block decoding on a vector of soft input data, ibits.

The value for CFI can be 1, 2, or 3. This value indicates the time span, in OFDM symbols, of the DCI PDCCH transmission (the control region) in that downlink subframe. For bandwidths in which NDLRB is greater than 10 RB, the span of the DCI in OFDM symbols is the same as the actual CFI value. If NDLRB is less than or equal to 10 RB, the span is CFI+1 symbols.

Data Types: int32

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

Was this topic helpful?