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NSN RRM overview
Citation preview
1 Nokia Siemens Networks RN31631EN40GLA0
RANPAR 1
RN 3163-40A
Nokia Siemens Networks
2 Nokia Siemens Networks RN31631EN40GLA0
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
R 255 G 211 B 8
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R 137 G 146 B 155
R 175 G 0 B 51
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R 0 G 0 B 0
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Primary colors: Supporting colors:
146 B 155
3 Nokia Siemens Networks RN31631EN40GLA0
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 & RRM HSPA+ features (Overview)
4 Nokia Siemens Networks RN31631EN40GLA0
Radio Resource Management (RRM) Overview: 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
5 Nokia Siemens Networks RN31631EN40GLA0
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 in accordance with user requests
Radio Resource Management (RRM) is responsible for optimal utilization of the air interface resources
RRM
Link Quality
Cell Coverage Cell Capacity
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RRM Tasks
RRM must be able to: Predict the impact on interference (power) of
the 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 real time (RT) and non-real time (NRT) users
Take appropriate corrective actions when the different cell load thresholds are exceeded in order to maintain cell stability (i.e. load control)
Overload
Load Target Overload Margin
Pow
er
Time
Estimated capacity for NRT traffic Measured load caused by 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 violating 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
RNC BTS MS
Power Control Handover Control Admission Control
Load Control Packet Scheduler
9 Nokia Siemens Networks RN31631EN40GLA0
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
Overload threshold x
Load Target threshold y
Pow
er
Time
Estimated capacity for NRT traffic.
Measured load caused by non-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
PS NRT load
Load change info
Load status
Load differentiation: Total load =
Controllable load + Semi-controllable load + Non-controllable load
11 Nokia Siemens Networks RN31631EN40GLA0
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 parameters for the radio link, e.g.: UL/DL BLER, Eb/No targets, SIR target Initial DL transmission power
AC takes place in the RNC
Admission Decision
Grant
Reject
12 Nokia Siemens Networks RN31631EN40GLA0
PS allocation times need to be fast to accommodate changing conditions & accurate (up-to-date load info)
Capacity requests sent via traffic volume measurement reports (governed by RNP parameters)
PS comprises two parts: UE specific & Cell specific HSDPA & HSUPA resources are scheduled by the Node B
power
time
non-controllable load controllable load
Total Load
Target threshold
Overload threshold Packet Scheduler in RNC schedules
radio resources for both UL & DL R99 NRT RABs
Scheduling period defined by RNP parameters
PS relies on up-to-date information from AC & LC
Capacity allocated on a needs basis using best effort approach
Packet Scheduler PS
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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 moves around network Maintaining connection quality by ensuring UE is always served by the best cell saving capacity
GSM/LTE GSM/LTE
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 selection codes concentrated to same branch Code de-fragmentation dynamic 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
15 Nokia Siemens Networks RN31631EN40GLA0
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 2 0 4 0 6 0 8 0 1 00 1 20 1 40 1 60- 202468
1 01 21 41 6
Time [number of TTIs]
QPS K1 /4
QPS K2 /4
QPS K3 /4
16QAM2/4
16QAM3/4
Instan
tane
ous E
sNo [d
B]
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HSUPA / Comparing HSUPA to R99 and HSDPA
HSUPA is 3GPP Rel6 Enhanced FDD Uplink main characteristics:
Peak Rates up to 5.76 Mbps with QPSK Up to 11.5Mbps with 16QAM (RU30) Fast WBTS Packet Scheduling Fast L1 HARQ algorithms Fast Link Adaptation 2ms or 10ms TTI periods Soft Handover SF down to SF = 2
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
17 Nokia Siemens Networks RN31631EN40GLA0
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
General Improvements: Fast Dormancy Multi-Band Load Balancing MBLB High Speed Cell_FACH (DL)
HSUPA Improvements: HSUPA 11Mbps (16QAM) Frequency Domain Equalizer HSUPA Interference Cancellation Receiver
DL Peak Rates up to: 42 Mbps UL Peak Rates up to: 11 Mbps
RU30
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HSPA+ Improvements HSDPA Improvements:
DC-HSDPA + 64QAM + MIMO (84Mbps) Dual Band HSDPA (42 Mbps)
General Improvements: High Speed Cell_FACH (DL+UL) Smart LTE Layering Application Aware RAN
DL Peak Rates up to: 84 Mbps UL Peak Rates up to: 11 Mbps
RU40
HSDPA Improvements: MC-HSDPA (168 Mbps) HSDPA Multiflow
General Improvements: Measurement based LTE Layering Conversational QoS for VoIP RAN Optimized Content Delivery
HSUPA Improvements: DC-HSUPA (23 Mbps)
DL Peak Rates up to: 168 Mbps UL Peak Rates up to: 23 Mbps
RU50 under planning