01_rn31634en10gla0_loadcontrol
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1 © Nokia Siemens Networks RN3007EN06GLN00I insert classification level
Course Content
Radio Resource Management Overview
Parameter Configuration
Common Channels & Power Control
Load Control
Admission Control
Packet Scheduling
Handover Control
Resource Manager
HSPA
2 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Module Objectives
At the end of the module you will be able to:
• Describe the difference between controllable and non-controllable loads
• Describe the difference between preventive and overload threshold
• Describe the relationships of Load Control with Admission Control and Packet Scheduler
• Name and describe summarily the main RAN parameters related to load control
3 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Load Control
• Load Control Functions
• Radio Interface Load• Power based Radio Resource Management
• Throughput based Radio Resource Management
• Planning thresholds for cell loading
• BTS Measurements and Reporting• Common Measurements
• Dedicated Measurements
• Filtering of Measurements
4 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Load Control Functional Overview
RRM in RNC
LC
AC
PS
Load change estimations
Load change estimations
Scheduling period
PRACH load measurement
WBTS NB/RSNBAP-PRIVATE:RRIndPeriod or3GPP NBAP :COMMONMEASUREMENTREPORT
Dedicated measurement reporting
parameters
parameters
measurements
estimations
when changed Load change info
Load status request
Load status
NRT load
measurements
5 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
BTS Measurements sent to CRNC
Common Measurements from Cell
WBTS – RADIO RESOURCE MEASUREMENT REPORT (private part)
NB/RS – COMMON MEASUREMENT REPORT
Dedicated Measurements from active users in Cell_DCH
WBTS – NB/RS DEDICATED MEASUREMENT REPORT
IuB
C - NBAP
D - NBAP
6 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Load Control
• Load Control Functions
• Radio Interface Load• Power based Radio Resource Management
• Throughput based Radio Resource Management
• Planning thresholds for cell loading
• BTS Measurements and Reporting• Common Measurements
• Dedicated Measurements
• Filtering of Measurements
7 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Load Estimation Methods
• Actual prevailing load in the cell depends on multiple factors
• Number of active connections
• Properties of the connections• Bit rate
• Eb/No requirement• BLER requirement
• Propagation channel conditions (speed, multipath profile etc.)
• SHO condition
• Activity
• Different methods can be applied to measure/estimate prevailing load conditions, e.g.
• Throughput Based Load Estimation
• Power Based Load Estimation
10 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
UL power based load measurement
PRx_Own
PRxTotal = PRx_Own + PRx_Other + PNoise
= PRx_NRT + PRx_RT + PRx_Other + PNoise
= PRx_NRT + PRx_NC
PRx_Other
iUL = PRx_Other / PRx_Own
11 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
DL power based load measurement
PTx_Own
PTxTotal = PTx_Own
= PTx_NRT + PTx_RT + PTx_Common
= PTx_NRT + PTx_NC
PTx_Common
Com
mon
Cha
nnel
s
PRx_Own_DL
PRx_Other_DL
iDL = PRx_Other_DL / PRx_Own_DL
12 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Radio Interface Load
• The BTS measures the total received power (PrxTotal) and the total transmitted power (PtxTotal) on cell basis
The BTS reports PrxTotal and PtxTotal of each cell to the RNC
LC updates
Cell load status for each cell based on RADIO RESOURCE INDICATION
Non-controllable UL (PrxNC) and DL (PtxNC) load in cell
Semi-controllable UL (Prx_SC) and DL (Ptx_SC) load in the cell (related to PS Streaming)
AC and PS algorithms work on the current cell load status provided by LC
Denying call admission (AC) and throttling back NRT traffic (PS) are the overload actions
After scheduling PS provides LC with PrxNRT, PtxNRT & LNRT estimates
After admitting RT RAB, AC provides LC with NC load increase estimate
13 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
System Noise
• System noise (WCEL: PrxNoise) is the sum of all stationary noises;• thermal noise
• interference caused by spurious emissions of other systems,
• noise caused by additional equipment such as repeaters
• PrxNoise can vary place to place and even time to time
• PrxNoise is a RNP parameter whose setting affects the capacity of cell• PrxNoise too low: overestimation of cell load and can lead to unnecessary call blocking
• PrxNoise too high: underestimation of cell load and can lead to overload situation
RNC calculates averaged PrxUnloaded values using a mean filter to remove temporary interference peaks
PrxNoise is updated by the autotuning algorithm based on PrxUnloaded
14 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
PrxNoise Autotuning Algorithm
• RNC provides tools to measure unloaded system noise, PrxUnloaded, and tools to adjust PrxNoise parameter based on these measurements
• PrxTotal = PrxUnloaded when own cell is considered unloaded (or very low load);
Own Cell;
LRT UnloadedRT and
LNRT UnloadedNRT and no EDCH users in the cell
UnloadedRT and UnloadedNRT are RNC parameters (values for NRT: 1 %, RT: 2 %)
LRT and LNRT are UL load factor for own cell RT (AC estimates) & PS users (PS estimates)
• RNC calculates averaged PrxUnloaded values using a mean filter to remove temporary interference peaks
• PrxNoise is updated by the autotuning algorithm based on PrxUnloaded
• PrxNoise autotuning step size is limited by PrxNoiseMaxTuneAbsolute parameter
15 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
UL Preventive & Overload Thresholds
Prx Target [dB]
PrxTarget [dB] + PrxOffset [dB]
load factor
Range [0..1]
Nois
e R
ise [
dB
]
Overloaded AreaOverload threshold = PrxTarget + PrxOffset
Overload Threshold defines the limit when the cell is considered to be overloaded
If load in the cell exceeds these limits then AC & PS move to OVERLOAD STATE function
New calls are blocked, and PS starts to decrease NRT bit rates in the cell
Marginal Load Area
Feasible Load Area
WCEL:PrxTarget (0…30dB)(0.1dB)(4dB)
WCEL:PrxOffset (0…6dB)(0.1dB)(1dB)
dBLog 110 10PrxTarget =
16 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
DL Preventive & Overload Thresholds
Ptx Target [dBm]
Ptx Target [dBm] + PtxOffset [dB]
load factor
tota
l tr
an
sm
itte
d
pow
er
Ptx T
ota
l [d
Bm
]
Overloaded Area
Marginal Load Area
Feasible Load Area
Cell Maximum
WCEL:PtxTarget (-10…PtxCellMax)(0.1dBm)(40dBm)
WCEL:PtxOffset (0…6dB)(0.1dB)(1dB)
WCEL:PtxCellMax(0…50dBm)(0.1dB)(43dBm)
17 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Load Control
• Load Control Functions
• Radio Interface Load• Power based Radio Resource Management
• Throughput based Radio Resource Management
• BTS Measurements and Reporting• Common Measurements
• Dedicated Measurements
• Filtering of Measurements
18 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
NB/RS situation
• Selected by WBTS:NBAPCommMode(0,1)(-)(-)
• 0=Nokia
• 1=Siemens
19 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Measurements taken and reported by NB/RSxxx
• Periodical reporting every 800ms or slower
• TCP – Transmitted Carrier Power
• Periodic and Event E reporting for non HSDPA cells
• Periodic for HSDPA cells
• Transmitted Code Power of all codes not used for HSDPA
• Periodic and Event E reporting for non HSDPA cells
• RTWP – Received Wideband Wideband Power
• Periodic and Event E reporting for non HSDPA cells for non-HSUPA cells
• Event E reporting for HSUPA cells
• RSEPS – Received Scheduled E-DCH Power Share
• Periodic and Event E reporting for HSUPA cells
• Acknowledged PRACH preambles
• Periodic reporting is used
24 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
WBTS situation
• Selected by WBTS:NBAPCommMode(0,1)(-)(-)
• 0=Nokia
• 1=Siemens
25 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Common measurements taken and reported by WBTS
• PtxTotal – Transmitted Carrier Power
• Nokia Private NBAP
• PtxNonHSPATransmitted Code Power of all codes not used for HSDPA
• Nokia Private NBAP
• PrxTotal – Received Wideband Wideband Power
• Nokia Private NBAP
• REPS – Received E-DCH Power Share
• Nokia Private NBAP
• Acknowledged PRACH preambles
• Nokia Private NBAP
• Provided HSDPA Bitrate
• Provided HSUPA Bitrate
• Required Power
RRM in RNC needs this information for Streaming mapped on HSPA(NST – Non Scheduled Transmission)
Nokia Private part is protocol extension specified in 3GPP
33 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
BTS measurements in RNC
NBAP-c in CRNC
RRM
Iub
Repetitions (dedicated measurements not repeated)
34 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Dedicated Measurements in BTS
• Transmitted Code Power• WBTS and NB/RSxxx send periodic measurement reports with code power
measurement results from all Radio Links (UEs in Cell_DCH)
• Depending on allocated service type WBTS applies different reporting frequency
• CS Services and SRBWBTS: DedicatedMeasRepPeriod Range and Step [0.5..5 s, step 0.5 s], step 0,5 sec
Default = 2.5 sec
• CS Data Services WBTS: DediMeasRepPeriodCSdata Range and Step [0.5..5 s, step 0.5 s], step 0,5 sec
Default = 1.5 sec
• PS Data ServicesWBTS: DediMeasRepPeriodPSdata Range and Step [0.5..5 s, step 0.5 s], step 0,5 sec
Default = 0.5 sec
35 © Nokia Siemens Networks RN3007EN06GLN00 Soc Classification level
Dedicated Measurements in BTS
• Uplink SIR Error
• HSPA Serving cell change feature makes use of UL SIR quality measurements to check the quality for HS-DPCCH reception
UE has RRC connection establishedHS-DSCH channel type is selected
AS>1
NBAP: Dedicated Measurement Initiation
NBAP: Dedicated Measurement Report
NBAP: Dedicated Measurement Report
NBAP: Dedicated Measurement Report
NBAP: Dedicated Measurement Report
Reporting frequency can be controlled:
RNC: HSDPASIRErrorReportPeriod
Range and Step: 0..10 sec, step 1 sec
Value “0” means “switched off”
Default: 0.5 sec
Measurement Filtering can be controlled:
RNC: HSDPASIRErrorFilterCoefficient
Range and Step: 0 (100 %), 1 (71 %), 2 (50 %), 3 (35 %),
4 (25 %), 5 (18 %), 6 (13 %), 7 (9 %), 8 (6 %), 9 (4 %), 11 (2 %)
Default: 5 (18%)
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