| KPI | Formula (Samsung counters) | Read it as |
|---|---|---|
| Per-leg HO SR | IntraGnbOut_Succ ÷ IntraGnbOut_Att · InterXnOut_Succ ÷ …Att · InterNgOut_Succ ÷ …Att (Fam 5197) | The three legs, source view; targets track LTE's >98% practice |
| Composite SA HO SR | Σ Succ ÷ Σ Att over the three legs | The headline; leg mix is itself diagnostic (Ng share = missing Xn) |
| HO time per leg | IntraGnb/InterXn/InterNg_HoTimeAvg/Max (Fam 5199) | Xn ≪ NG by design — an NG-dominant cell needs Xn build-out |
| EPS Fallback SR (voice-critical) | InterSysLTE_Out_EPSFallback_Succ ÷ …_Att (Fam 5229) | Every failure is an unplaced voice call — hold to accessibility-grade targets |
| IRAT leave mix | HO (5211) vs redirection (RedirectionToLTE_CoverageOut, 5176) vs fallback (5229) | Redirection share rising = coverage forcing downgrades |
| Ping-pong rate | Pingpong, Pingpong1…8 (Fam 5210) ÷ HO attempts | <5% (LTE practice carried over) |
| Cancel share | *_HandoverCancel ÷ attempts (all legs) | Prepared-then-abandoned — churn in the decision layer |
HandoverCancel (the source aborts a prepared HO — target got worse, or a better candidate appeared) and *_RRE (the HO collapsed into a re-establishment — the rescue caught it; see the SA retainability page's Family 5203). A rising RRE share means your mobility is being saved by the recovery machinery — fix the trigger before the rescue wears out.An SA handover threads every interface of the split gNB: the CU-CP decides, E1 moves the bearer context (CU-UP), F1 builds the target DU context, Xn/NG carries the inter-gNB leg, RRC moves the UE (t304 — now per-5QI/per-slice profiled). The counter grammar names each joint:
| Token | Meaning | First place to look |
|---|---|---|
IntraGnbOut/In · InterXnOut/In · InterNgOut/In | The leg + the view (source/target) | Ng-leg share high = Xn missing to real neighbours (the S1-vs-X2 lesson, upgraded) |
…PrepFail_<E1|F1|Xn|Ng|Cp><TimeOut|Fail> | Preparation — which interface refused/never answered | E1=CU-UP · F1=DU · Xn=peer gNB · Ng=AMF · Cp=CU-CP internal |
…Fail_RrcTimeOut | Execution — the UE never completed at the target | Trigger placement + t304 profile + target beam/RACH |
…HandoverCancel | Prepared, then abandoned by the source | Decision-layer churn — candidate ranking, CHO where licensed |
…RRE | Collapsed into re-establishment | The rescue path (5203, retainability page) caught a failed move |
InterFreqOutWithGap_* (5235) | Inter-frequency legs with measurement gaps — full domain split repeated | Gap variant failing = scheduler starving gaps (capacity), not coverage |
InterSysLTE_Out_* / _EPSFallback_* / _EmergencyFallback_* (5211/5229) | Leaving NR: mobility vs voice-driven fallback — separately counted | _N26InterfaceNotAvailable = the 5GC↔EPC bridge is down (core, verbatim counter) |
RedirectionToLTE_CoverageOut / _EPSFallback / _EmergencyFallback (5176) | Redirection with its reason — the cheap exit | Coverage-out share rising = NR footprint lagging; a roadmap signal |
PduSetupFail_E1Fail, ReEstabFail_E1Timeout and InterXnOut_PrepFail_E1TimeOut rise together has one CU-UP/E1 problem, not three feature problems. Cross-page correlation beats per-KPI tuning every time.| Leg · feature | Signature counters | Optimization (deck-verbatim where quoted) |
|---|---|---|
| Intra-gNB · FGR-MC1008 | IntraGnbOut_* / IntraGnbIn_* — incl. inter-DU vs intra-DU moves | F1/E1 timeouts inside one gNB = midhaul/CU-UP; deck's F1 params: t1-DUSetupWait 3 s; HO-failure recovery behaviour chapter |
| Inter-gNB Xn · FGR-MC1010 | InterXnOut_PrepFail_XnTimeOut/_XnFail | The fast path; deck Case-3 values: set-inter-xn-prep-timeout 150→200 ms ("reduces prep failures by 35%"), xn-status-transfer-enhancement-on-off = On |
| Inter-gNB NG · FGR-MC1009 | InterNgOut_PrepFail_NgTimeOut/_NgFail | The AMF-anchored fallback; its share is the Xn-coverage KPI — build Xn to top NG pairs |
| Timing (5199) | IntraGnb/InterXn/InterNg_HoTimeAvg | Deck latency chapter: T304 hand-in 50→100–150 ms for high-speed UEs ("reduces fast-failing handovers by 40%") |
| Trigger · FGR-MC1007 | A3 config; Pingpong1…8 (5210) | Deck: A3-offset −6→−4 dB triggers earlier; TTT 480→160 ms high-mobility; handover-margin-nr 3→1–2 dB dense |
The deck dedicates 30 slides to MC1006. The core table, verbatim — priority-based reselection with the ThreshX ladder plus ranking with Qhyst:
| Parameter | Recommended (deck) | Reason (verbatim) |
|---|---|---|
| ThreshX_HighP | −105 dBm | Smooth transitions to higher-priority RATs/frequencies during coverage issues or congestion |
| ThreshX_HighQ | −3 dB | High-quality reselection for better user experience |
| ThreshX_LowP | −115 dBm | Prevents premature reselection to lower-priority frequencies while the current cell is usable |
| ThreshX_LowQ | −6 dB | Avoids reselection to low-quality cells unless absolutely necessary |
| S_IntraSearchP / S_IntraSearchQ | −110 dBm / −5 dB | UE starts intra-frequency measurements only when coverage deteriorates |
| TreselectionNR | 1000 ms | Prevents ping-pong reselections, stabilizes UE behaviour |
| Qhyst | 3–6 dB | Reduces frequent reselections from marginal fluctuations |
| Qoffset | 0 dB high-prio · 3–5 dB low-prio | Promotes reselection to higher-priority cells, delays transitions down |
| Qqualmin / Qrxlevmin | −6 dB / −120 dBm | Camp only on acceptable-quality cells / never on extremely weak ones |
cell-reselect-intra-freq-info parameter set, inter-RAT NR↔LTE reselection strategy, and the ranking-criterion optimization. Paging lives in Families 5186 (AttPaging/DiscardedPaging) with overload twins 5180/5185 — same TA-plan hygiene as LTE.Three exits, three costs: handover (seamless, expensive), redirection (cheap, a service break), fallback (voice-driven, latency-critical). Family 5229 splits EPS fallback from Emergency fallback — and counts the killer cause by name: InterSysLTE_Out_EPSFallback_N26InterfaceNotAvailable — the 5GC↔EPC bridge itself is down.
| Exit | Counters | Playbook |
|---|---|---|
| IRAT HO out/in (5211/5212) | InterSysLTE_Out_Att/PrepSucc/Succ + PrepFail_Ng*/Cp* + Fail_E1/F1/Ng* + HandoverCancel + RRE + N26InterfaceNotAvailable | The seamless exit; PrepFail_Ng* = AMF/N26 path — core work, not radio |
| Redirection (5176/5234) | RedirectionToLTE_CoverageOut / _EPSFallback / _EmergencyFallback · RedirectionToNR_CoverageOut | The cheap exit — reason-split. CoverageOut trending up = NR footprint roadmap item, not a parameter |
| EPS / Emergency fallback (5229) | InterSysLTE_Out_EPSFallback_* / _EmergencyFallback_* — full prep/exec/cancel/RRE split each | Voice accessibility in disguise: hold fallback SR to setup-grade targets; failures = unplaced calls. Watch _N26InterfaceNotAvailable separately — one core event, mass failures |
_EPSFallback) is faster than HO-based (5229) but breaks data continuity — choose per market; measure call-setup time end-to-end, not just the SR.Feed the serving and neighbour measurements plus the deck's parameters; the calculator runs both NR reselection rules — the priority ladder (ThreshX) and the equal-priority ranking (Qhyst/Qoffset) — and tells you where the UE camps and why.
| Parameter | Typical / default | Deck guidance (verbatim where quoted) |
|---|---|---|
| A3-offset (handover-mobility-configuration) | −6 dB (case) | Case 3: −6→−4 dB "triggers earlier handover" |
| time-to-trigger | 480 ms | "160 ms — faster handovers in high mobility"; 320 ms urban recommendation in the MC1007 chapter |
| handover-margin-nr | 3 dB | "1–2 dB — less aggressive handovers in dense areas" |
| t304-for-fr1 / t304-for-fr2 + per-5QI/slice profiles | release default | Deck T304 chapter: service-specific profiles via ra-timer-profile-usage/-index (per 5QI and per S-NSSAI); hand-in T304 50→100–150 ms high-speed ("reduces fast-failing handovers by 40%") |
| set-inter-xn-prep-timeout | 150 ms | Case 3: →200 ms "increases E1 interface timing tolerance… reduces prep failures by 35%" |
| xn-status-transfer-enhancement-on-off | Off | →On "reduces UE context transfer delay" (shared with the retainability rescue) |
| Frequency-priority mobility (FGR-MC1022) | — | PCell frequency prioritization + CA-aware HO by A2 + SA-prioritization wait timer (three sub-features, deck chapter) |
Baseline the legs + the exits
5197/5198 per leg with prep/exec split, 5199 timing, 5210 ping-pong, the IRAT triple (5211/5176/5229), paging 5186. Compute composite, leg mix and cancel/RRE shares.
three legs · three exits · two new outcomes Skip this and fallback failures hide inside "mobility looks fine".Check the leg mix
NG share high = Xn missing to real neighbours (build Xn, don't tune). Cancel share high = decision churn (candidate ranking / CHO). RRE share high = the rescue is carrying your mobility.
mix before parameters If wrong: trigger tuning for a topology gap.Split prep vs exec — the domain names the team
Prep _E1/_F1 = split-gNB internals · _Xn = peer/transport · _Ng = AMF. Exec _RrcTimeOut = trigger/t304/target beam. Correlate domains across pages (one E1 problem ≠ three KPI problems).
Guard the voice path
EPS fallback SR (5229) at setup-grade + fallback latency; _N26InterfaceNotAvailable watched as a core alarm; Emergency fallback always clean.
Apply ONE lever
Trigger: A3-offset/TTT/handover-margin-nr per deck values. Timing: T304 profiles (per-5QI for voice!). Interfaces: xn-prep-timeout, status-transfer. Idle: the MC1006 table. One lever per soak.
deck values as starting points If wrong: unattributable results.Verify with the guards
Leg SRs up; ping-pong <5%; RRE/cancel shares down; redirection mix not degraded; retainability page's release families untouched.
same hour, before/after, cross-page guards If wrong: an SR gain bought with redirections is a downgrade.SA mobility is three legs, three exits, one shared grammar.
The E1/F1/Xn/Ng domains you learned on Day 2 decode every mobility failure too. Read the mix, then the domain, then tune. Compare with LTE's four quadrants and NSA's choreography to complete Day 3.1.
Sources: Samsung 5G NR Counter Description (CU-CP ACPF — Families 5197 HO_OUT / 5198 HO_IN (intra-gNB, Xn, NG legs), 5199 HO_TIME, 5235/5236 inter/intra-frequency, 5210 PINGPONG, 5211/5212 HO_EUTRAN, 5229 HO_EUTRAN_OUT_FALLBACK (EPS + Emergency incl. N26InterfaceNotAvailable), 5176 REDIR_EUTRAN_OUT, 5234 REDIR_NR_OUT, 5186/5180/5185 paging — counters verbatim) · 5G NR Mobility Optimization SA deck (FGR-MC1006 Idle Mobility incl. the reselection parameter table verbatim, MC1007 Connected Mobility Control, MC1008/1009/1010 the three legs, MC1018 Fast RLF Recovery, MC1022 Frequency-Priority Mobility with its three sub-features; T304 per-5QI/S-NSSAI profile chapter; Case-3 handover tuning values). Procedures per 3GPP TS 38.331 / 38.423 / 38.413. The re-establishment rescue (5203) and forced-mobility releases live on the SA retainability page — cross-referenced, not duplicated.