Band situation
Frequency range + SSB SCS fixes the case, Lmax and the start-symbol pattern — TS 38.213 §4.1
RRC config
ssb-PositionsInBurst bitmap
Toggle which candidate beams you actually transmit — the RRC bitmap updates live (MSB = SSB index 0).
Active beams
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Bitmap (binary / hex)
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Common questions
What is an SSB burst in 5G NR?
The SS/PBCH block (SSB) carries PSS, SSS and PBCH in 4 OFDM symbols. A burst is the set of up to L_max time-multiplexed SSB candidates transmitted within the first 5 ms of a period — each candidate on its own beam, which is how NR sweeps coverage during initial access.
What determines L_max (4, 8 or 64)?
Carrier frequency: ≤ 3 GHz allows 4 SSBs, 3–7.125 GHz allows 8, and FR2 allows 64. More beams at higher frequencies compensate for narrower beamwidths needed to overcome path loss.
What are SSB cases A to E?
Cases map SSB SCS to exact start symbols (TS 38.213 §4.1): A = 15 kHz {2,8}+14n, B = 30 kHz {4,8,16,20}+28n, C = 30 kHz {2,8}+14n, D = 120 kHz and E = 240 kHz for FR2 with 64 candidates. The case fixes precisely where in the half-frame each beam may fire.
What SSB periodicity should I configure?
For initial cell search UEs assume 20 ms. Shorter (5/10 ms) speeds up beam acquisition and handover at the cost of overhead; longer (40–160 ms) saves energy on capacity layers whose users were already acquired elsewhere.
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