Ts is the LTE basic time unit, 1/(15000*2048) s = about 32.55 ns.

LTE Timing Advance to Distance Calculator (TA → km)

Q: How far is one LTE Timing Advance step?

One TA step advances timing by 16*Ts = about 0.52 microseconds, which corresponds to about 78 metres of one-way distance.

Q: What is the maximum LTE cell range from TA?

The initial TA field is 11 bits (0 to 1282). At about 78 m per step that gives a maximum of roughly 100 km.

Q: Is 5G NR timing advance the same?

No. 5G NR timing advance scales with subcarrier spacing (numerology), so the step size differs from LTE's fixed 78 m.

Timing Advance command (0 – 1282)

The initial TA in the Random Access Response is 11 bits (0–1282), giving up to ~100 km.

How it worksThe TA ↔ distance formula

The eNodeB tells the UE to advance its uplink timing so all UEs' signals arrive aligned. The advance is quantised in steps of 16·T_s, where the LTE basic time unit T_s = 1/(15000×2048) s ≈ 32.55 ns:

step time = 16 × T_s = 16 / (15000 × 2048) ≈ 0.5208 µs

distance (one-way) = TA × (c × 16 × T_s) / 2 ≈ TA × 78.07 m

TA range 0–1282 → 0 – 100.1 km

The factor of ½ is because TA compensates the round trip (UE→eNB→UE), but the cell radius is the one-way distance. In 5G NR the granularity depends on subcarrier spacing (16·64·T_c/2^µ), so NR steps are finer than LTE's fixed 78 m — see the SSB tools.

FAQFrequently asked questions

How far is one LTE Timing Advance step?

One TA step (TA = 1) advances timing by 16·T_s ≈ 0.52 µs, which corresponds to about 78 metres of one-way UE–eNodeB distance.

What is the maximum LTE cell range from TA?

The initial TA field is 11 bits (0–1282). At ~78 m per step that gives a maximum of about 100 km, which sets LTE's largest usable cell radius.

What is Ts in LTE?

T_s is the LTE basic time unit, T_s = 1/(15000×2048) s ≈ 32.55 ns — the sample period at the 30.72 MHz reference rate divided down.

Is 5G NR timing advance the same?

No. NR TA uses 16·64·T_c scaled by 2^µ for the subcarrier spacing, so the step (and resolution) changes with numerology and is finer than LTE's fixed 78 m.

LTE Timing Advance → Distance

How it worksThe TA ↔ distance formula

FAQFrequently asked questions

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