Why is SLIV used in 5G NR?

SLIV is used to reduce signaling overhead, keep control messages compact, and ensure deterministic decoding at the receiver.

How is SLIV calculated?

SLIV is calculated by mapping the Start Symbol (S) and Length (L) to a unique integer value. The mapping depends on whether (L-1) is less than or equal to 7.

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Time Domain

SLIV Calculator

Encode and decode Start and Length Indicator Values (SLIV) for 5G NR PDSCH/PUSCH time domain resource allocation.

Parameter Control

Start Symbol (S)

sym

Length (L)

sym

Analysis Console

No Allocation

Understanding SLIV

What is SLIV?

5G NR SLIV stands for Start-Length Indicator Value. It’s a compact way used in 5G New Radio (NR) to describe where a transmission starts in time and how long it lasts, all with a single number.

"SLIV is a compact encoding used in 5G NR to describe the start position and duration of a transmission in the time domain using a single value."

Start Symbol (S): Which OFDM symbol in the slot the transmission begins.
Length (L): How many consecutive symbols the transmission occupies.

Why SLIV Exists?

Instead of signaling S and L separately, NR combines them into one integer called SLIV for efficiency.

✓Reduces signaling overhead (important for fast scheduling)
✓Keeps control messages like DCI compact
✓Ensures deterministic decoding at the receiver

How SLIV Works

Valid values of S and L are mapped to a unique SLIV number through a bijective mapping.

The Mechanism

The mapping is bijective (no ambiguity). The receiver decodes SLIV → recovers S and L. You normally don’t compute SLIV by hand—this is handled by the gNB scheduler and UE firmware.

Constraint

0 < L ≤ 14 - S

Where It's Used

PDSCH (Downlink)

PUSCH (Uplink)

DCI Messages

Related Tools

GSCN Calculator

Convert GSCN to Frequency

SLIV Calculator

Encode and decode Start and Length Indicator Values (SLIV) for 5G NR PDSCH/PUSCH time domain resource allocation.

Parameter Control

Start Symbol (S)

sym

Length (L)

sym

Analysis Console

No Allocation

Understanding SLIV

What is SLIV?

5G NR SLIV stands for Start-Length Indicator Value. It’s a compact way used in 5G New Radio (NR) to describe where a transmission starts in time and how long it lasts, all with a single number.

"SLIV is a compact encoding used in 5G NR to describe the start position and duration of a transmission in the time domain using a single value."

Start Symbol (S): Which OFDM symbol in the slot the transmission begins.
Length (L): How many consecutive symbols the transmission occupies.

Why SLIV Exists?

Instead of signaling S and L separately, NR combines them into one integer called SLIV for efficiency.

✓Reduces signaling overhead (important for fast scheduling)
✓Keeps control messages like DCI compact
✓Ensures deterministic decoding at the receiver

How SLIV Works

Valid values of S and L are mapped to a unique SLIV number through a bijective mapping.

The Mechanism

The mapping is bijective (no ambiguity). The receiver decodes SLIV → recovers S and L. You normally don’t compute SLIV by hand—this is handled by the gNB scheduler and UE firmware.

Constraint

0 < L ≤ 14 - S

Where It's Used

PDSCH (Downlink)

PUSCH (Uplink)

DCI Messages

Related Tools

GSCN Calculator

Convert GSCN to Frequency

SLIV Calculator

Parameter Control

Analysis Console

Understanding SLIV

What is SLIV?

Why SLIV Exists?

How SLIV Works

The Mechanism

Where It's Used

Related Tools

Related Technical Articles & Tools

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SLIV Calculator

Parameter Control

Analysis Console

Understanding SLIV

What is SLIV?

Why SLIV Exists?

How SLIV Works

The Mechanism

Where It's Used

Related Tools

Related Technical Articles & Tools

Beam Failure Detection and Recovery Procedure in 5G NR

Measurement Report: Event A4 in 5G NR

T319 RRC Timer in 5G NR

Conditional Handover (CHO) in 5G NR Release 16

SMTC in 5G NR: Measurement Timing Configuration Guide