Current MOBIFONE Hanoi DCS 1800 – GSM 900 Macro Mobility strategy

DCS 1800 – GSM 900 Macro Mobility strategy Main HO Parameters

MO ParameterID Parameter Name HO Type ScenarioGCELLBASICPARA LAYER Layer of the cell

Inter Layer HO

From higher layer to lower layer

(GSM900 -> DCS1800)

GCELLBASICPARA PRIOR Cell Priority

Inter Layer HO

GCELLHOBASIC HOTHRES Inter-layer HO Threshold

Inter Layer HO

GCELLHOBASIC LEVHOHYST Inter-layer HO Hysteresis

Inter Layer HO

G2GNCELLINTELEVHOHYST

Adjacent Cell Inter-layer HO Hysteresis

Inter Layer HO

G2GNCELL LEVSTAT Layer HO Watch TimeInter Layer HO

G2GNCELL LEVLAST Layer HO Valid TimeInter Layer HO

GCELLHOBASIC ULEDGETHRES Edge HO UL RX_LEV Threshold Edge HO

When serving cell signal < Edge HO threshold

GCELLHOBASIC DLEDGETHRES Edge HO DL RX_LEV Threshold Edge HO

G2GNCELLEDGEADJSTATTIME Edge HO AdjCell Watch Time Edge HO

G2GNCELLEDGEADJLASTTIME Edge HO AdjCell Valid Time Edge HO

G2GNCELL PBGTMARGIN PBGT HO Threshold PBGT HO

Between cells same layerG2GNCELL PBGTSTAT PBGT Watch Time PBGT HO

G2GNCELL PBGTLAST PBGT Valid Time PBGT HO

Layer HOINTELEVHOHYST = 68HOTHRES = 38LEVHOHYST = 2

Target > (38 + 68-64) + 2 = 40 ~ -70dBm

EDGE HO

Serving Cell < 30 ~ -80dBm

Case: Hard/No handover from DCS 1800 to GSM 900 cause poor quality

Phenomenon Base on actual DT test, we found some cases Hard/No

Handover from DCS 1800 to GSM 900 cell cause poor quality

Analysis Base on Layer 3 signaling message and OMC configuration data, we found that all

EDGE HO condition already fulfill to trigger HO from DCS1800 cell (13025) to GSM900 (13022)

- RxLev of serving cell (~-100dBm) < Edge HO DL RX_LEV Threshold- P/N Criterion: 4/6 MR the receiving level of the serving cell

is always smaller than the edge HO threshold The possible reason is BSC already trigger HO and send HO command to MS.

However cause by too poor DL signal and bad RF quality (RxQual 6~7) so MS can not decode HO received HO command and trigger HO to suitable target cell

Suggestion To avoid bad quality cause by No Handover/Hard to

Handover from DCS1800 to GSM900 cell, we can adjust following parameters to try trigger earlier

*Note: Current Mobifone already set DLEDGETHRES of DCS1800 cell > 30 (Default 20), so this parameters not suggest to increase more)

MO ParameterID Parameter NameCurrent Value

Suggest Value

G2GNCELLEDGEADJSTATTIME

Edge HO AdjCell Watch Time 6 3

G2GNCELLEDGEADJLASTTIME

Edge HO AdjCell Valid Time 4 2