01 rn31631en30gla1 ranpar1 rrm overview v1.2
TRANSCRIPT
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Soc Classification level
1 Nokia Siemens Networks RN31631EN30GLA1
RANPAR 1
RN 3163-30A
Nokia Siemens Networks
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Soc Classification level
2 Nokia Siemens Networks RN31631EN30GLA1
Course Objectives
Explain how NSN RRM is working, what
is measured, when & where Describe the purpose of each RRM
functional entities
Identify the relations between different
RRM functional entities
Describe the parameter database
structure
Describe the main RRM parameters
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Course Content
Radio Resource Management Overview
Parameter Configuration
Common Channels & Power Control
Load Control
Admission Control
Packet Scheduling
Handover Control
Resource Manager
HSDPA basics & RRM
HSUPA basics & RRMHSPA+ features (Overview)
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Module Objectives
At the end of the module you will be able to:
Describe the purpose of RRM
List the RRM functional entities
Describe the purpose of each RRM functional entity
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Radio Resource Management
Target for RRM is to ensure the RAN offers:
The planned coverage for each targeted service
High capacity i.e. low blocking (new calls, handovers)
The required Quality of Service (QoS)
Optimize the use of available capacity (priorities)
By continuously monitoring/adjusting how the available resources are used inaccordance with user requests
Radio Resource Management (RRM) is responsible for optimal
utilization of the air interface resources
RRM
Link Quality
Cell CoverageCell Capacity
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RRM Tasks
RRM must be able to:
Predict the impact on interference (power) ofthe admitting a new user for UL & DL
Perform appropriate actions (e.g. new call
admissions, bitrate increase/decrease etc.) in
accordance with prevailing load conditions
Provide different quality of service for realtime (RT) and non-real time (NRT) users
Take appropriate corrective action when the
different cell load thresholds are exceeded in
order to maintain cell stability (i.e. load
control)
Overload
Load Target
Overload Margin
Power
Time
Estimated capacityfor NRT traffic
Measured load causedby non-controllable load
(RT)
RT services must have higher quality assurance than NRT
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RRM is made up of a number of closely interdependent functions (i.e.
algorithms)
These functions can be divided into;
Cell Based
Load Control (LC)
Admission Control (AC)
Packet Scheduling (PS)
Resource Manager (RM)
Connection Based
Handover Control (HC)
Power Control (PC)
RRM Functional Split
PC
HC
Connection based functions
LC
AC
Cell based functions
PS
RM
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Power Control PC
WCDMA systems are interference limited; therefore, it is beneficial to reduce
transmission power as far as possible (without violate the required quality). Thus, the target of PC is to achieve the min. SIR that is required to offer
sufficient quality of the connection.
PC works on a per-connection basis.
Power Control
Power Control
Load Control
RNCBTSMS
Power ControlHandover Control
Admission Control
Load Control
Packet Scheduler
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Load Control functions
The load control function within RRM can be divided:
Preventative load control(e.g. congestion)
Overload control(e.g. dropping of calls in worst case)
Preventative actions are performed before the cell is overloaded (threshold y)
Overload actions are performed after cell is overloaded (threshold x)
RNP parameters define the thresholds for the RRM functionalities
The thresholds define a stable functionality within a cell & with surrounding cells
Overloadthreshold x
Load Targetthreshold y
Power
Time
Estimated capacity for
NRT traffic.
Measured load caused bynon-controllable load (RT)
Preventative Load Control
Overload Control
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Load Control LC
LC performs the function of load control in association with Admission Control AC &
Packet Scheduling PS
Updates load status using measurements & estimations provided by AC & PS
Continuously feeds cell load information to PS & AC:
Interference levels BTS power levels
Non-controllable load
LC
AC
PSNRT load
Load change info
Load status
Load differentiation:
Total load =
Controllable load +
Semi-controllable load +
Non-controllable load
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Admission Control AC
Checks that admitting a new user will not sacrifice planned
coverage or quality of existing connections
Determines whether RABs or RRC connections can be
admitted
Handles RT RABs by estimating the increase in non-controllable load
In the decision UL interference & DL power measurements by BTS
are used
Since RAS06 the UL throughput is considered for AC, too
UL & DL admission conditions must both be fulfilled to admit a new
call or modified existing call
Provides RLC parameters to PS for NRT users, e.g.
Bearer class
Transport Formats
AC sets quality and power parametersfor the radio link, e.g.: UL/DL BLER, Eb/No targets, SIR target
Initial DL transmission power
AC takes place in the RNC
AdmissionDecision
Grant
Reject
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Handover Control HC
Intra-Frequency Handovers Softer/Soft Handover
UE simultaneously connected to multiple
cells from same/different Node Bs
Mobile Evaluated Handover MEHO
Hard Handover
when Inter-RNC SHO is not possible
(Iur not supported or Iur congestion)
in case of HSDPA
Inter-Frequency Handover can be Intra-BS, Intra-RNC or Inter-RNC
Network Evaluated Handover NEHO
Inter-RAT Handover Handovers between WCDMA and GSM, LTE or WLAN
Network Evaluated Handover NEHO
WCDMA F1 WCDMA F1 WCDMA F1
WCDMA F2 WCDMA F2
WCDMA F1
HC is responsible for:
Managing the mobility aspects of an RRC connection as UE move around network
Maintaining connection quality by ensuring UE is always served by best cell saving capacity
GSM GSM
WCDMA
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Resource Manager RM
Responsible for managing the logical radio resources of the RNC in co-operation with
AC and PS
On request for resources, from either AC(RT) or PS(NRT), RM allocates:
DL Channelization Code
UL Scrambling Code
cares about code tree management (to maintain orthogonality);
Initial code selectioncodes concentrated to same branch
Code de-fragmentationdynamic reallocation of codes as users enter/leave system
DL spreading code allocation for HSDPA users can be dynamic from RAS06 on
Code Type Uplink Downlink
Scrambling codes
Channelization codes
User separation Cell separation
Data & control channels from same UE Users within one cell
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HSDPA - general principle
Fast scheduling is done directly in Node-B based on feedback information from UE
and knowledge of current traffic state.
Hard Handover only
UE2
Channel quality(CQI, Ack/Nack, TPC)
Channel quality(CQI, Ack/Nack, TPC)
Data
Data
Users may be time and/or code multiplexed
New WBTS functions:
Fast HARQ retransmissions
Fast Adaptive Modulation & Coding
Fast Packet data scheduling (short TTI)
UE1
0 20 40 60 80 100 120 140 160-2
02468
10121416
Time [ number of TTIs]
QPSK1/4
QPSK2/4
QPSK3/4
16QAM2/4
16QAM3/4
I
nstantaneousEsNo[dB]
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HSUPA / Comparing HSUPA to R99 and HSDPA
HSUPA is 3GPP Rel6 Enhanced FDD Uplink
main characteristics:
Fast WBTS Packet Scheduling
Fast L1 HARQ algorithms
Fast Link Adaptation
2ms or 10ms TTI periods
Soft Handover
SF down to SF = 2
Peak Rates up to 5.76 Mbps
Feature
Rel99
DCH
Rel5
HSDPA
Rel6
HSUPA
Var. spreading factor Y N Y
Fast power control Y N Y
Adaptive modulation N Y N
WBTS based scheduling N Y Y
Fast L1 HARQ N Y Y
Soft Handover Y N Y
TTI length [ms] 80,40,20,10 2 10,2
E-DCH
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HSPA+ Improvements
Improving the DL peak rates, cell throughput & spectrum efficiency:
64QAM: Enhanced HSDPA Modulation
MIMO: Intelligent Multi-Antenna Systems DC-HSDPA: Dual-Carrier/Cell Transmission
Improving the cell throughput & spectrum efficiency:
DL Flexible RLC
Continuous Packet Connectivity
CS Voice over HSPA
DL Peak Rates up to: 21/28/42 Mbps
UL Peak Rates up to: 5.8 Mbps
RU20
DL Peak Rates up to: 84 Mbps
UL Peak Rates up to: 5.8 Mbps
HSDPA Improvements:
DC-HSDPA + 64QAM + MIMO
General Improvements:
Fast Dormancy
Multi-Band Load Balancing MBLB
HSUPA Improvements:
Frequency Domain Equalizer
HSUPA Interference Cancellation
ReceiverRU30