RNC Dimensioning ProcessBased on ICSU Control Plane Load

RNC dimensioningICSU load – RNC2600 CP rule

• This rule gives an indication of the RNC capacity in terms of control plane processing.

• The rule cannot be used in isolation, the result has to be combined with the other capacity limits of the RNC.

• ICSU CPU load calculation is based on the number of signalling events and so-called „CPU cost” of each event.

Check RNC Control Plane Load

RNC dimensioningICSU load – RNC2600 CP rule

• List of relevant signalling events having impact on Control Plane load.Event: Description:

PagingAmount of pagings in 1 second

NAS signaling

Amount of NAS signaling messages in 1 second including SMSs. LACs, RACs, IMSI attach/detach, SCC, SRNS Relocations

SHO Amount of Soft Handovers in 1 second

CS callCS call attempts in 1 second

PS call PS call attempts (RT and NRT), Rel99 and HSDPA in 1 second

DCH-FACH

Amount of state transictions between Cell_DCH and Cell_FACH in 1 second

HS-DSCH-FACH

Amount of state transitions between Cell_DCH (incl. HS-DSCH) and Cell_FACH in 1 second

DCH-PCH

Amount of state transitions between Cell_DCH (incl. HS-DSCH) and Cell_PCH in 1 second

FACH-PCH

Amount of state transictions between Cell_FACH and Cell_PCH in 1 second

NBAP measurements

Amount of dedicated NBAP measurements in 1 second

RNC dimensioningICSU load – RNC2600 CP rule – Step 1/3

• Derive frequency of the signalling events from traffic profile [1/s].• Calculate aggregated loads, separately for CS/PS –related and common procedures, using the following formulas (i – particular event) :

• weight[i] = offset[i] + gradient[i]*RRCoCCH[%]

0

0

0

][i]frequency[__

][i]frequency[__

][i]frequency[__

i

i

i

iweightoncontributiBHCAcommon

iweightoncontributiBHCAPS

iweightoncontributiBHCACS

 RU20 offset RRCoCCH gradient

Paging 93 -1.4NAS 2399 -964SHO 1580 -23.2CS call 3995 -712.6PS call 5602 -1601DCH-FACH 1545 -257.6HS-DSCH-FACH 1404 -234DCH-PCH 1375 -229.2FACH-PCH 307 -51NBAP meas 41 -0.6

RNC dimensioningICSU load – RNC2600 CP rule – Step 2/3

• Calculate “mixed BHCA limit” for concrete RNC Capacity Step according to the following equation:

– where:– max_CS_BHCA and max_PS_BHCA – BHCA limitations for concrete RNC capacity step and inlude NAS signalling– CS_PS_ratio has to be calculated using following formula:

Where:

BHCAPSratioPSCSBHCACSratioPSCSitBHCAMixed _max_*)__1(__max_*__lim__

ratioonlyPSratioonlyCSratioonlyCSratioPSCS

________

oncontributiBHCAcommonBHCACSoncontributiBHCACSratioonlyCS___max_

____

oncontributiBHCAcommonBHCAPSoncontributiBHCAPSratioonlyPS___max_

____

RNC dimensioningICSU load – RNC2600 CP rule – Step 3/3

• Finally, check if calculated aggregated BHCA loads don’t exceed mixed_BHCA_limit:

1lim__

______

itBHCAmixed

oncontributiBHCAcommononcontributiBHCAPSoncontributiBHCACS

Formula Explanation1. CS_BHCA_Contributions, PS_BHCA_Contributions, Common_BHCA_Contributions:

i. Frequency: From measurementii. Weight: Constant from table

2. Max_CS_BHCA = CS_BHCA + NAS_BHCA per Subs * Max CS_Subs – All constant from Product Specification

3. Max_PS_BHCA = PS_BHCA + NAS_BHCA per Subs * Max PS_Subs– All constant from Product Specification

4. CS_only_ration, PS_only_ratio: calculation from measurement with contant table and constant from product specification

RNC dimensioningICSU load – RNC CP rule – Measurements (1/2)

Event Counter Counter Name Frequency Fomula

CS call

M1001C66 RAB_STP_ATT_CS_VOICE

=(M1001C66 + M1001C67 + M1001C68 + M1001C599 + M1001C653 + M1001C655 + M1001C657) / DURATION

M1001C67 RAB_STP_ATT_CS_CONV

M1001C68 RAB_STP_ATT_CS_STREAM1001C599

RAB_STP_ATT_CS_VOICE_WPSM1001C653

RAB_RELOC_STP_ATT_CS_VOICEM1001C655

RAB_RELOC_STP_ATT_CS_CONVM1001C657

RAB_RELOC_STP_ATT_CS_STREA

PS call

M1001C70 RAB_STP_ATT_PS_STREA

=(M1001C70 + M1001C71 + M1001C72 + M1001C651 + M1001C817 + M1001C826) / DURATION

M1001C71 RAB_STP_ATT_PS_INTER

M1001C72 RAB_STP_ATT_PS_BACKG

M1001C651 RAB_RELOC_STP_ATT_PS_STREA

M1001C817 RAB_RELOC_STP_ATT_PS_INT

M1001C826 RAB_RELOC_STP_ATT_PS_BGRPaging M1003C36 REC_PAG_MSG =M1003C36 / DURATION

SHO

M1007C10CELL_ADD_REQ_ON_SHO_FOR_RT

=((M1007C10 + M1007C12) / (SHO RT) + (M1007C27 + M1007C29) / (SHO NRT)) / DURATION

M1007C12CELL_REPL_REQ_ON_SHO_FOR_RT

M1007C27CELL_ADD_REQ_ON_SHO_FOR_NRT *) SHO RT and SHO NRT see below

M1007C29CELL_REPL_REQ_ON_SHO_FOR_NRT

DCH-FACH M1006C45 CELL_DCH_STATE_TO_CELL_FACH =(M1006C45 + M1006C46) / DURATION - "HS-DSCH-FACH"M1006C46 CELL_FACH_STATE_TO_CELL_DCH

RNC dimensioningICSU load – RNC CP rule – Measurements (2/2)

Event Counter Counter Name Frequency Fomula

HS-DCH-FACH M1006C154 SUCC_HS_DSCH_TO_FACH =(M1006C154 + M1006C152) / DURATIONM1006C152 SUCC_FACH_TO_HS_DSCH

FACH-PCH M1006C48 CELL_FACH_STATE_CELL_PCH_UPD =(M1006C48 + M1006C47) / DURATION

M1006C47 CELL_FACH_STATE_CELL_PCH_INA

DCH-PCHM1006C114 CELL_DCH_STATE_TO_CELL_PCH

=(M1006C114 +M1006C197) / DURATIONM1006C197 SUCC_PCH_DCH_TRANS_UMRLC

NAS, M1001C0 RRC_CONN_STP_ATT

=(M1001C0 + M1001C808 + M1008C222 + M1008C223)/DURATION - "CS call" - "PS call"

Serving Cell ChangeM1001C808 RRC_RELOC_STP_ATT

M1008C222 SCC_INTRA_BTS_SUCCESSFUL M1008C223 SCC_INTER_BTS_SUCCESSFULNBAP M1005C148 DEDIC_MEAS_REPORT =M1005C148 / DURATION

SHO RT

M1007C0ONE_CELL_IN_ACT_SET_FOR_RT

=(M1007C0 + M1007C1 * 2 + M1007C2 * 3 - M1007C6 * 2) / (M1007C0 + M1007C1 + M1007C3 - M1007C6)

M1007C1TWO_CELLS_IN_ACT_SET_FOR_RT

M1007C2THREE_CELLS_IN_ACT_SET_RT

M1007C6SOFTER_HO_DUR_ON_SRNC_FOR_RT

SHO NRT

M1007C19ONE_CELL_IN_ACT_SET_FOR_NRT

=(M1007C19 + M1007C20 * 2 + M1007C21 * 3 - M1007C25 * 2) / (M1007C19 + M1007C20 + M1007C21 - M1007C25)

M1007C20TWO_CELLS_IN_ACT_SET_FOR_NRT

M1007C21THREE_CELLS_IN_ACT_SET_NRT

M1007C25SOFTER_HO_DUR_ON_SRNC_NRT

ICSU Load Calculation vs Measurement