lteSCI

Sidelink control information format structure and bit payload

Syntax

[sciout,bitsout] = lteSCI(ue)

[sciout,bitsout] = lteSCI(ue,sciin)

[sciout,bitsout] = lteSCI(ue,bitsin)

[sciout,bitsout] = lteSCI(___,opts)

Description

[sciout,bitsout] = lteSCI(ue) returns a sidelink control information (SCI) message structure, sciout, and the SCI message bit vector, bitsout, for the settings specified in the user equipment structure.

This function creates and manipulates SCI format 0 messages, defined in TS 36.212 [1], Section 5.4.3. You can use lteSCI to create a default SCI message, to blindly decode SCI format types, and to determine the sizes of the bit fields.

By default, all returned fields are set to zero.

[sciout,bitsout] = lteSCI(ue,sciin) returns the SCI structure fields and bit vector using settings specified in SCI input structure sciin. Fields not defined in sciin are set to defaults specified by ue. You can use this syntax to initialize SCI field values, in particular the frequency hopping bit, which affects the fields that the format uses.

[sciout,bitsout] = lteSCI(ue,bitsin) returns the SCI structure fields and bit vector using settings specified in bit input vector bitsin. The input bit vector is returned as the SCI information bit payload, where bitsout == bitsin.

[sciout,bitsout] = lteSCI(___,opts) formats the returned structure using options specified by opts.

Examples

Create SCI Message

Create a format 0 SCI message structure.

Create a UE settings structure.

ue = struct('NSLRB','15MHz');

Generate an SCI message and view the returned SCI message structure contents.

[sci0,bits] = lteSCI(ue);
sci0

sci0 = struct with fields:
              SCIFormat: 'Format0'
            FreqHopping: 0
             Allocation: [1×1 struct]
    TimeResourcePattern: 0
              ModCoding: 0
            TimeAdvance: 0
                  NSAID: 0

allocfields = sci0.Allocation

allocfields = struct with fields:
    RIV: 0

Create SCI Message with Distributed VRB Allocation Type

Create a format 0 SCI message structure with the distributed VRB allocation type. The allocation message fields are contained in the Allocation substructure. To create the appropriate set of fields at the output, the FreqHopping field is initialized at the input to the function.

Create a UE settings structure and define FreqHopping using an input SCI message structure.

ue = struct('NSLRB',50);
sciin = struct('FreqHopping',1);

Generate an SCI message and view the returned SCI message structure contents.

[sci0,bits] = lteSCI(ue,sciin);
sci0

sci0 = struct with fields:
              SCIFormat: 'Format0'
            FreqHopping: 1
             Allocation: [1×1 struct]
    TimeResourcePattern: 0
              ModCoding: 0
            TimeAdvance: 0
                  NSAID: 0

allocfields = sci0.Allocation

allocfields = struct with fields:
    HoppingBits: 0
            RIV: 0

Recover SCI Message from Bit Vector

Recover the contents of a format 0 SCI message bit vector.

Create a UE settings structure.

ue = struct('NSLRB',50);

Generate an SCI message structure.

[sci0,bits] = lteSCI(ue);
sci0

sci0 = struct with fields:
              SCIFormat: 'Format0'
            FreqHopping: 0
             Allocation: [1×1 struct]
    TimeResourcePattern: 0
              ModCoding: 0
            TimeAdvance: 0
                  NSAID: 0

Change the ModCoding setting to 22 and generate an SCI bits vector.

sci0.ModCoding = 22;
[~,bits_new] = lteSCI(ue,sci0);

Use the new bits to recover the new SCI message. View the new SCI message structure and confirm that the ModCoding setting is now 22.

[sci0_new,~] = lteSCI(ue,bits_new)

sci0_new = struct with fields:
              SCIFormat: 'Format0'
            FreqHopping: 0
             Allocation: [1×1 struct]
    TimeResourcePattern: 0
              ModCoding: 22
            TimeAdvance: 0
                  NSAID: 0

View SCI Message Field Sizes

Create a format 0 SCI message structure. Use the opts input to view the message field sizes and to exclude fields with zero length.

Create a UE settings structure.

ue = struct('NSLRB','5MHz');
opts = {'fieldsizes','excludeunusedfields'}

opts = 1×2 cell
    {'fieldsizes'}    {'excludeunusedfields'}

Generate an SCI message and view the field sizes of the returned SCI message structure contents.

[sci0,bits] = lteSCI(ue,opts);
sci0

sci0 = struct with fields:
              SCIFormat: 'Format0'
            FreqHopping: 1
             Allocation: [1×1 struct]
    TimeResourcePattern: 7
              ModCoding: 5
            TimeAdvance: 11
                  NSAID: 8

allocfields = sci0.Allocation

allocfields = struct with fields:
    RIV: 9

Inspect the returned structure to see the bit length of each field in the SCI message.

fieldsLength = sci0.FreqHopping + sci0.Allocation.RIV + ...
    sci0.TimeResourcePattern + sci0.ModCoding + sci0.TimeAdvance + ...
    sci0.NSAID

fieldsLength = uint64

41

bitsLength = size(bits,1)

bitsLength = 
41

isequal(fieldsLength,bitsLength)

ans = logical
   1

The sum of the field sizes matches the length of the returned bits output.

Input Arguments

ue — User equipment settings

structure

User equipment settings, specified as a structure containing these parameter fields:

PSSCHNSubchannels — Number of sub-channels in the V2X PSSCH resource pool

1 (default) | integer scalar from 1 to 110 | optional

Number of sub-channels in the V2X PSSCH resource pool, specified as an integer scalar from 1 to 110. You must specify this input when you set the sciin to 'Format1'.

Data Types: double

NSLRB — Number of sidelink resource blocks

integer scalar from 6 to 110

Number of sidelink resource blocks, specified as an integer scalar from 6 to 110.

Example: 6, which corresponds to a channel bandwidth of 1.4 MHz.

Data Types: double

opts — Formatting options for output SCI structure

character vector | cell array of character vectors | string array

Formatting options for output SCI structure, specified as a character vector, cell array of character vectors, or a string array. You can specify a format for the Field content and Fields to include. 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):

Category	Options	Description
Field content	'fieldvalues' (default)	Set the fields to zero or to their input values.
	'fieldsizes'	Sets the field values to their bit sizes and adds the Padding field to sciout. Padding indicates the number of padding bits appended.
Fields to include	'includeallfields' (default)	sciout includes all possible fields for the requested SCI format.
	'excludeunusedfields'	sciout excludes zero-length fields for the given parameter set.

Example: 'fieldsizes excludeunusedfields', "fieldsizes excludeunusedfields", {'fieldsizes','excludeunusedfields'}, or ["fieldsizes","excludeunusedfields"] specify the same formatting options.

Data Types: char | string | cell

sciin — SCI message settings

structure

SCI message settings, specified as a structure containing any fields returned in sciout. See sciout for the specific fields output for each SCIFormat. SCI format 0 message is defined in TS 36.212 [1], Section 5.4.3.1. It can contain the following field:

SCIFormat — SCI format type

'Format0' (default) | 'Format1'

SCI format type, specified as 'Format0' or 'Format1'.

Data Types: char | string

Data Types: struct

bitsin — Input bits

column vector

Input bits, specified as a column vector. bitsin is treated as the SCI message bit payload, that is, bitsout == bitsin. The length of bitsin must align with the number of resource blocks, ue.NSLRB. Use lteSCIInfo to determine SCI message length for the specified ue settings.

Data Types: double

Output Arguments

sciout — SCI message structure

structure

SCI message structure, returned as a structure whose fields match the associated SCI format contents.

The field names associated with sciout depend on the SCI format field in sciin. By default, all values are set to zero. However, if any of the SCI fields are already present in the input sciin, their values are carried forward into sciout. The input field values appear in the associated bit positions in bitsout. Carrying the values forward allows for easy initialization of SCI field values. sciout also carries forward the NSLRB field specified in sciin.

This table presents the fields associated with each SCI format, as defined in TS 36.212 [1], Section 5.4.3.1.

SCI Formats	sciout Fields	Size	Description
'Format0'	SCIFormat	-	'Format0'
	FreqHopping	1 bit	PSSCH frequency hopping flag
	Allocation	from 5 to 13 bits, $$\lceil {\log }_2\left(\frac{N_{\text{RB}}^{\text{SL}}\times \left(N_{\text{RB}}^{\text{SL}}+1\right)}{2}\right)\rceil$$	Resource block assignment and hopping resource allocation substructure, type 0 or type 1 allocation
	TimeResourcePattern	7 bits	Time resource pattern (ITRP)
	ModCoding	5 bits	Modulation and coding scheme (IMCS)
	TimeAdvance	11 bits	Timing advance indication
	NSAID	8 bits	Group destination ID, as defined by higher layers
	Padding	0 bits	Always zero for SCI Format 0
'Format1'	SCIFormat	-	'Format1'
	Priority	3 bits	Per packet priority
	ResourceReservation	4 bits	Resource reservation
	RIV	from 0 to 13 bits, $$\lceil {\log }_2\left(\frac{N_{\text{subchannel}}^{\text{SL}}\times \left(N_{\text{subchannel}}^{\text{SL}}+1\right)}{2}\right)\rceil$$	Resource indication value
	TimeGap	4 bits	Time gap between initial transmission and retransmission
	ModCoding	5 bits	Modulation and coding scheme
	RetransmissionIdx	1 bit	Retransmission index

bitsout — SCI message in bit payload form

column vector of binary values

SCI message in bit payload form, returned as a column vector. bitsout represents the set of message fields mapped to the information bit payload (including any zero-padding).

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 R2016b