Quality requirements for application-to-bearer mapping (Cont.)
Traf Tr affi fic c dema demand nd cal calcu cula lati tion on Speech Spe ech,, video video tel teleph ephony ony,, and and PS PS RT ser servic vices es Speech, voice telephony, and PS RT services are characterised by:
Busy-hour-call-attempts (BHCA) [ ]
Call duration [s]
Bearer rate (Information rate) [kbit/s]
Activity (DCH-activity) [ ]
The traffic demand calculates as follows: Traffic_Volume[kb] = no_subscribers * BHCA * Call_Duration * Bearer_Rate * DCH_activity
Throughput[kbps] =
Traffic_Volume[kb] 3600s
Traffic_Demand[mErl] =
no_subscribers * BHCA * Call_Duration * 1000 3600
Note that for voice services the DCH activity depends on the interface in the UTRAN to be considered. Typical assumptions on the activity on the air interface are 0.5 (optimistic) – 0.67 (conservative). Note that for PS RT Services served by a multi-RAB the traffic demand for the supporting PS interactive/background RAB needs to be calculated.
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Dimensioning WCDMA RAN
2.2.4.2
PS data services (Release 99) Relevant parameters for calculating the traffic demand for PS I/B Release 99 services are:
Busy-hour-call-attempts (BHCA) [ ]
DCH (session) duration [s]
Bearer rate (Information rate) [kbit/s]
Activity (DCH-activity) [ ]
The traffic demand calculates as follows: Traffic_Volume[kb] = no_subscribers * BHCA * DCH_Duration * Bearer_Rate * DCH_activity
Throughput[kbps] =
Traffic_Volume[kb] 3600s
Traffic_Demand[mErl] =
no_subscribers * BHCA * DCH_Duration * 1000 3600
Note that one DCH session per BHCA without channel type switching is assumed. In case of channel type switching, the DCH session is interrupted. All parts of the DCH session can be added to a single DCH duration. Channel type switching is included in the signaling traffic demand by the number of CTS events assumed per (PS) subscriber. DL
DCH
FACH
data rate
* SHO in DL
DCH
DL bearer (peak) rate DL mean rate during DCH session DL mean rate over RAB life t
UL
DCH
RACH
data rate
* SHO in UL
DCH
UL bearer (peak) rate UL mean rate during DCH session UL mean rate over RAB life time to switch from DCH to FACH
For more information regarding relevant signaling procedures (in particular Channel Type Switching, Bit Rate Adaptation, and Soft or Softer Handover), see Dimensioning signaling traffic in Dimensioning interfaces.
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Dimensioning WCDMA RAN
2.2.4.3
PS data services (Release 5) Relevant parameters for calculating the traffic demand for PS I/B Release 5 - HSDPA services are:
Busy-hour-call-attempts (BHCA)]
HS-DSCH (session) duration (s)
Mean throughput per user during HS-DSCH session (Kbit/s)
The UL traffic demand is calculated as described in the previous section for Release 99 DCH sessions. The DL traffic demand is calculated as follows: Traffic_Volume[kb] = no_subscribers * BHCA * HS_DSCH_Duration * Nominal_Peak_Rate * HS_DSCH_activity Throughput[kbps] =
The parameters above are alternatively expressed by: MeanThroughputPerUser_during_HS_DSCH_session[kbps] = Nominal_Peak_Rate * HS_DSCH_activity
Note that one HS-DSCH session per BHCA without channel type switching is assumed. In case of channel type switching, the HS-DSCH session is interrupted. All parts of the HS-DSCH session can be added up to a single HS-DSCH duration. Channel type switching is included in the signaling traffic demand by the number of CTS events assumed per (PS) subscriber. DL
HS-DSCH
HS-DSCH
FACH
data rate
HS-DSCH (nominal) peak rate
mean rate during HS-DSCH session mean rate over RAB life t RAB life duration (incl. RACH/FACH periods) time to switch from HS-DSCH to FACH HS-DSCH session duration (excl. RACH/FACH periods) UL
DCH
Figure 15
RACH
DCH
* SHO in UL
HSDPA session overview (focus on DL)
For more information regarding relevant signaling procedures (in particular HS Channel Type Switching), see Dimensioning signaling traffic in Dimensioning interfaces.
DN70118376 Issue 03E
Id:0900d805805d8dbc
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Dimensioning WCDMA RAN
2.2.4.4
PS data services (Release 6) Relevant parameters for calculating the traffic demand for PS I/B Release 6 - HSxPA services are:
Busy-hour-call-attempts (BHCA)
E-DCH (session) duration (s)
Mean Throughput per user during E-DCH session (kbit/s)
The DL traffic demand is calculated as described in the previous section for Release 5 HS-DSCH sessions. The UL traffic demand calculates as follows: Traffic_Volume[kb] = no_subscribers * BHCA * E_DCH_Duration * Nominal_Peak_Rate * E_DCH_activity
The parameters above are alternatively expressed by: MeanThroughputPerUser_during_E_DCH_session[kbps] = Nominal_Peak_Rate * E_DCH_activity
Note that one E-DCH session per BHCA without channel type switching is assumed. In case of channel type switching, the E-DCH session is interrupted. All parts of the E-DCH session can be added to a single E-DCH duration. Channel type switching is included in the signaling traffic demand by the number of CTS events assumed per (PS) subscriber. Note that because the HS-DSCH duration and E -DCH duration are identical, UL E-DCH is always accompanied by DL HS-DSCH. DL
HS-DCH
FACH
HS-DCH
UL
E-DCH
RACH
E-DCH
data rate
* SHO in U
E-DCH (nominal) peak rate mean rate during E-DCH session mean rate over RAB life time to switch from HS-DSCH/E-DCH to FACH
For more information on relevant signaling procedures (in particular HS Channel Type Switching and HSUPA Soft/Softer Handover), see Dimensioning signaling traffic in Dimensioning interfaces.
