01 Rn31631en30gla1 Ranpar1 Rrm Overview v1.2

8/13/2019 01 Rn31631en30gla1 Ranpar1 Rrm Overview v1.2

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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


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

Documents

01 Rn31631en30gla1 Ranpar1 Rrm Overview v1.2