lteEPDCCHDMRS

EPDCCH demodulation reference signals

Syntax

sym = lteEPDCCHDMRS(enb,chs)

sym = lteEPDCCHDMRS(enb,chs,opts)

Description

sym = lteEPDCCHDMRS(enb,chs) returns the Enhanced Physical Downlink Control Channel Demodulation Reference Signal (EPDCCH DM-RS) symbols for transmission in a single subframe. By default the symbols are returned as a column vector. The order of the symbols is the same as the order that results when you use lteEPDCCHDMRSIndices to map them into an N-by-M-by-4 array. This array represents the resource element subframe grid across the four possible EPDCCH antenna ports (p = 107...110).

The symbols are parameterized in terms of a configured PRB pair set which defines:

• the overall set of possible EPDCCH candidates and

• the aggregation of one or more consecutive enhanced control channel elements (ECCE). This aggregation identifies the specific EPDCCH instance that the DM-RS is associated with.

The DM-RS symbols are created only for the specific PRB pairs and antenna ports that the corresponding EPDCCH is mapped to.

For a localized EPDCCH transmission, the EPDCCH is associated with a single antenna port from p = 107...110, dependent on the chs.RNTI and ECCEs selected. Thus, the DM-RS antenna port symbols are output only for that single port.

For a distributed transmission, the EPDCCH is mapped to two antenna ports in an alternating fashion. Therefore, the DM-RS symbols are generated for the PRBs in both ports: p = 107,109 for normal cyclic prefix and p = 107,108 for extended cyclic prefix. The output is ordered so that the symbols for the lowest antenna ports index come first. This order matches that of the DM-RS RE indices produced by lteEPDCCHDMRSIndices.

sym = lteEPDCCHDMRS(enb,chs,opts) allows control of the format of the symbols through the options specified by opts. You can use this syntax to return the symbols as a numeric matrix, where each column contains symbols for an active antenna port.

This function performs no precoding. If necessary, apply precoding externally.

Examples

Generate EPDCCH DM-RS Symbols

Specify the cell-wide settings and channel transmission configuration in parameter structures enb and chs.

enb.NDLRB = 6;
enb.NSubframe = 0;
chs.EPDCCHECCE = [0 7];
chs.EPDCCHType = 'Localized';
chs.EPDCCHPRBSet = 2:3;
chs.EPDCCHNID = 0;
chs.RNTI = 1;

Generate EPDCCH demodulation reference signal symbols.

sym = lteEPDCCHDMRS(enb,chs)

sym = 12×1 complex

   0.7071 - 0.7071i
   0.7071 + 0.7071i
   0.7071 + 0.7071i
  -0.7071 + 0.7071i
   0.7071 - 0.7071i
   0.7071 - 0.7071i
   0.7071 + 0.7071i
   0.7071 - 0.7071i
   0.7071 + 0.7071i
  -0.7071 - 0.7071i
      ⋮

Note: The warning messages generated simply advise you that default values are available and being used for uninitialized parameters. To suppress warnings for defaulted lte parameter settings, precede code with the following command: lteWarning('off','DefaultValue')

Generate DM-RS Symbols for EPDCCH Having a Distributed Transmission

Specify the cell-wide settings and channel transmission configuration in parameter structures enb and chs.

enb.NDLRB = 6;
enb.NSubframe = 0;
chs.EPDCCHECCE = [0,7];
chs.EPDCCHType = 'Distributed';
chs.EPDCCHPRBSet = 2:3;
chs.EPDCCHNID = 0;
chs.RNTI = 1;

Generate DM-RS symbols for an EPDCCH having a distributed transmission. Return the symbols as a matrix, where each column contains symbols for an active antenna.

sym = lteEPDCCHDMRS(enb,chs,'mat')

sym = 12×2 complex

   0.7071 - 0.7071i   0.7071 - 0.7071i
  -0.7071 - 0.7071i  -0.7071 - 0.7071i
   0.7071 + 0.7071i   0.7071 + 0.7071i
   0.7071 - 0.7071i   0.7071 - 0.7071i
   0.7071 - 0.7071i   0.7071 - 0.7071i
  -0.7071 + 0.7071i  -0.7071 + 0.7071i
  -0.7071 - 0.7071i  -0.7071 - 0.7071i
   0.7071 - 0.7071i   0.7071 - 0.7071i
  -0.7071 - 0.7071i  -0.7071 - 0.7071i
  -0.7071 - 0.7071i  -0.7071 - 0.7071i
      ⋮

Note: The warning messages generated simply advise you that default values are available and being used for uninitialized parameters. To suppress warnings for defaulted lte parameter settings, precede code with the following command: lteWarning('off','DefaultValue')

Input Arguments

enb — eNodeB cell-wide settings

structure

eNodeB cell-wide settings, specified as a structure containing these parameter fields:

Parameter Field	Required or Optional	Values	Description
NDLRB	Required	Scalar integer from 6 to 110	Number of downlink resource blocks ($$N_{\text{RB}}^{\text{DL}}$$)
CyclicPrefix	Optional	'Normal' (default), 'Extended'	Cyclic prefix length
NSubframe	Required	0 (default), nonnegative scalar integer	Subframe number
DuplexMode	Optional	'FDD' (default), 'TDD'	Duplexing mode, specified as one of the following: 'FDD' — Frequency division duplex (default) 'TDD' — Time division duplex
The following parameters apply when DuplexMode is set to 'TDD'.
TDDConfig	Optional	0, 1 (default), 2, 3, 4, 5, 6	Uplink–downlink configuration
SSC	Optional	0 (default), 1, 2, 3, 4, 5, 6, 7, 8, 9	Special subframe configuration (SSC)

chs — Channel-specific channel transmission configuration

structure

Channel-specific transmission configuration, specified as a structure containing these parameter fields:

Parameter Field	Required or Optional	Values	Description
EPDCCHECCE	Required	One-element or two-element vector specifying the zero-based ECCE index or inclusive [begin, end] ECCE index range according to the aggregation level L (L = end – begin + 1). The number of ECCEs in the candidate must be one of: a power of 2 12 (since R2024b) 24 (since R2024b) If no transmission is required, leave this parameter empty.	Set of one or several consecutive ECCEs defining the EPDCCH transmission candidate in the overall EPDCCH set
EPDCCHType	Required	'Localized', 'Distributed'	EPDCCH transmission type
EPDCCHPRBSet	Required	Vector of zero-based indices for the PRB pairs corresponding to the EPDCCH PRB set. The number of PRB pair indices must be one of: a power of 2 6 (since R2024b) If no transmission is required, leave this parameter empty.	EPDCCH PRB pair indices
EPDCCHNID	Required	Nonnegative scalar integer	EPDCCH nID parameter for scrambling sequence initialization
RNTI	Required only when EPDCCHType is set to 'Localized'	0 (default), scalar integer	Radio network temporary identifier (RNTI) value (16 bits)

opts — Symbol generation options

character vector | cell array of character vectors | string array

Symbol generation options, specified as a character vector, cell array of character vectors, or string array. For convenience, you can specify several options as a single character vector or string scalar by a space-separated list of values placed inside the quotes. Values for opts when specified as a character vector include (use double quotes for string):

Option	Values	Description
Symbol style	'ind' (default), 'mat'	Style for the returned symbols, specified as one of the following: 'ind' — returns the symbols as a column vector (default) 'mat' — returns the symbols as a matrix in which each column contains symbols for an active antenna port from the set p = 107...110
Symbol format	'rsonly' (default), 'rs+unused'	Format of the returned symbols. 'rsonly' — returns only active DM-RS symbols (default) 'rs+unused' — also returns zeros for the RE locations, which should be unused because of EPDCCH DM-RS transmission on other EPDCCH antenna ports p = 107...110 that are not used by this EPDCCH transmission.

Example: 'ind rs+unused', "ind rs+unused", {'ind','rs+unused'}, or {"ind","rs+unused"} specify the same formatting options.

Data Types: char | string | cell

Output Arguments

sym — EPDCCH DM-RS symbols

numeric column vector | numeric matrix

EPDCCH demodulation reference signal symbols, returned as a column vector containing the non-precoded DM-RS symbol sequences concatenated for all active PRB pairs and antenna ports. Optionally, the function returns sym as a numeric matrix, where each column contains symbols for an active antenna port.

Data Types: double

Version History

Introduced in R2014b

R2024b: Reference signals for MPDCCH Format 5

The lteEPDCCHDMRS function now supports MTC physical downlink control channel (MPDCCH) Format 5. To get reference symbols for this MPDCCH format, specify the EPDCCHECCE field as a two-element vector that defines 12 or 24 ECCEs and the EPDCCHPRBSet field as a vector of length 6. Both fields belong to the chs input structure.