ERAN Capacity Monitoring Guide

eRAN7.0

Capacity Monitoring Guide

Issue DraftA

Date 2014-1-20

HUAWEI TECHNOLOGIES CO., LTD.

Issue DraftA (2014-1-20) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd.

i

Copyright Huawei Technologies Co., Ltd. 2014. All rights reserved.

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eRAN7.0 Capacity Monitoring Guide About This Document



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About This Document

Purpose

Growing traffic in mobile networks requires more and more resources. Lack of resources will

affect user experience. This document provides guidelines on LTE FDD capacity monitoring

including details on how to identify resource allocation problem and on how to monitor

network resource usage. Capacity monitoring provides data reference for network

reconfiguration and capacity expansion and enables maintenance personnel to take measures

before resources insufficiency affects network QoS and user experience.

NOTE

For definitions of the man-machine language (MML) commands, parameters, alarms, and

performance counters mentioned in this document, see the "Operation and Maintenance" part in

3900 Series LTE eNodeB Product Documentation for eNodeB base station, BTS3202E Product

Documentation for BTS3202E base station, and BTS3203E LTE Product Documentation for

BTS3203E base station.

For the BTS3202E and the BTS3203E LTE, the main control unit, transmission unit, and baseband

unit share the CPU because they are integrated into the same board, called BTS3202E board or

BTS3203E LTE board. The main control board and the baseband board mentioned in this document

correspond to the BTS3202E board or BTS3203E LTE board, and the CPU usage of the main

control board corresponds to that of the BTS3202E board or BTS3203E LTE board.

This document is not applicable to scenarios with large capacity and heavy traffic. For guidelines in

such scenarios, contact Huawei technical support.

Product Versions

The following table lists the product version related to this document.

Product Name Product Version

DBS3900 V100R009C00

The mapping single-mode base station version is:

eNodeB: V100R007C00 BTS3900

BTS3900A

BTS3900L

BTS3900AL

BTS3202E

BTS3203E

eRAN7.0 Capacity Monitoring Guide About This Document



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Intended Audience

This document is intended for:

Field engineers

Network planning engineers

Change History

This section describes changes in each issue of this document.

Draft A (2014-1-20)

Draft A (2014-1-20)

This is the first draft.

eRAN7.0 Capacity Monitoring Guide Contents



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Contents

About This Document .................................................................................................................... ii

1 Overview ......................................................................................................................................... 1

1.1 Network Resources .......................................................................................................................................... 1

1.2 Capacity Monitoring Methods.......................................................................................................................... 3

2 Capacity Monitoring..................................................................................................................... 4

2.1 Introduction ...................................................................................................................................................... 4

2.2 Downlink User Perception ............................................................................................................................... 5

2.2.1 Monitoring Principles ............................................................................................................................. 5

2.2.2 Monitoring Methods ............................................................................................................................... 6

2.2.3 Suggested Measures ................................................................................................................................ 6

2.3 PRACH Resource Usage .................................................................................................................................. 6




2.4 PDCCH Resource Usage .................................................................................................................................. 7




2.5 Connected User License Usage ........................................................................................................................ 8




2.6 Paging Resource Usage .................................................................................................................................... 9




2.7 Main-Control-Board CPU Usage ................................................................................................................... 10

2.7.1 Monitoring Principles ........................................................................................................................... 10

2.7.2 Monitoring Methods ............................................................................................................................. 10

2.7.3 Suggested Measures .............................................................................................................................. 10

2.8 LBBP CPU Usage .......................................................................................................................................... 11


eRAN7.0 Capacity Monitoring Guide Contents



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2.9 Transport Resource Group Usage ................................................................................................................... 12




2.10 Ethernet Port Traffic ..................................................................................................................................... 13

2.10.1 Monitoring Principles ......................................................................................................................... 13

2.10.2 Monitoring Methods ........................................................................................................................... 13

2.10.3 Suggested Measures ............................................................................................................................ 14

3 Resource Allocation Problem Identification ......................................................................... 15

3.1 Resource Congestion Indicators ..................................................................................................................... 15

3.1.1 RRC Resource Congestion Rate ........................................................................................................... 16

3.1.2 E-RAB Resource Congestion Rate ....................................................................................................... 16

3.2 Resource Allocation Problem Identification Process ..................................................................................... 16

4 Related Counters ......................................................................................................................... 18

eRAN7.0 Capacity Monitoring Guide 1 Overview



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1 Overview This chapter describes the types of network resources to be monitored and the method of

performing capacity monitoring.

1.1 Network Resources

Figure 1-1 shows the network resources to be monitored.

Figure 1-1 Network resources to be monitored

Table 1-1 describes the types of network resources to be monitored and impacts of resource

insufficiency on the system.




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Table 1-1 Network resources

Resource Type Meaning Impact of Resource

Insufficiency on

the System

Monitoring Item

Cell

resources

Physical resource

blocks (PRBs)

Bandwidth consumed

on the air interface

Users may fail to

be admitted, and

experience of

admitted users is

affected.

Downlink User

Perception

Physical random

access channel

(PRACH) resources

Random access

preambles carried on

the PRACH

Access delays are

prolonged, or

even access

attempts fail.

PRACH Resource

Usage

Physical downlink

control channel

(PDCCH) resources

Downlink control

channel resources

Uplink and

downlink

scheduling delays

are prolonged,

and user

experience is

affected.

PDCCH Resource

Usage

eNodeB

resources

Connected user

license

Maximum permissible

number of users in

RRC_CONNECTED

mode

New services

cannot be

admitted, and

experience of

admitted users is

affected.

Connected User

License Usage

Paging resources eNodeB paging

capacity

Paging messages

may be lost,

affecting user

experience.

Paging Resource

Usage

Main-control-board

CPU

Processing capability of

the main control board

of the eNodeB

KPIs deteriorate. Main-Control-Board

CPU Usage

LTE baseband

process unit (LBBP)

CPU

Processing capability of

the LBBP board

KPIs deteriorate. LBBP CPU Usage

Transport resource

groups

eNodeB logical

transport resources

Packets may be

lost, affecting

user experience.

Transport Resource

Group Usage

Ethernet ports eNodeB physical

transport resources

Packets may be

lost, affecting

user experience.

Ethernet Port Traffic




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1.2 Capacity Monitoring Methods

Capacity monitoring can be implemented using the following two methods:

Daily monitoring for prediction: Counters are used to indicate the load or usage of

various types of resources on the LTE network. Thresholds for resource consumption are

specified so that preventive measures such as reconfiguration and expansion can be taken

to prevent network congestion when the consumption of a type of resource continually

exceeds the threshold. For details, see chapter 2 "Capacity Monitoring."

Problem-driven analysis: This method helps identify whether a problem indicated by

counters is caused by network congestion through in-depth analysis. With this method,

problems can be precisely located so that users can work out a proper network

optimization and expansion solution. For details, see chapter 3 "Resource Allocation

Problem Identification."

Thresholds defined for capacity monitoring in this document are generally lower than those for

alarm triggering so that risks of resource insufficiency can be detected as early as possible.

Thresholds given in this document apply to networks experiencing a steady growth. Thresholds are

determined based on experiences. For example, the connected user license usage threshold 60% is

specified based on the peak-to-average ratio (about 1.5:1). When the average usage reaches 60%,

the peak usage approaches 100%. Threshold determining considers both average and peak values.

Telecom operators can define thresholds based on the actual situation.

Telecom operators are encouraged to formulate an optimization solution for resource capacity

based on prediction and analysis for networks that are experiencing fast development, scheduled to

deploy new services, or about to employ new charging plans. If you require services related to

resource capacity optimization, such as prediction, evaluation, optimization, reconfiguration, and

capacity expansion, contact Huawei technical support.

eRAN7.0 Capacity Monitoring Guide 2 Capacity Monitoring



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2 Capacity Monitoring This chapter describes monitoring principles and methods, as well as related counters, of all

types of service resources. Information about how to locate resource bottlenecks and the

related handling suggestions are also provided.

Note that resource insufficiency may be determined by usage of more than one type of service

resource. For example, a resource bottleneck can be claimed only when both connected user

license usage and main-control-board CPU usage exceed the predefined thresholds.

2.1 Introduction

You need to determine busy hours of the system for accurate monitoring of counters. You are advised to

define busy hours as a period when the system or a cell is undergoing the maximum resource

consumption of a day.

Table 2-1 describes types of resources to be monitored, thresholds, and handling suggestions.

Table 2-1 Types of resources to be monitored, thresholds, and handling suggestions

Resource Type

Monitoring Item Conditions Handling Suggestions

Cell

resources

Downlink User

Perception

Downlink PRB usage 70% and downlink user-perceived rate < 2

Mbit/s (default value,

user-configurable)

Add carriers or

eNodeBs.

PRACH Resource Usage Usage of preambles for

contention-based access 75% Enable the adaptive

Backoff or resource

adjustment algorithm for

the PRACH.

Usage of preambles for

non-contention-based access 75% Enable the PRACH

resource adjustment

algorithm and reuse of

dedicated preambles

between UEs.




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Resource Type

Monitoring Item Conditions Handling Suggestions

PDCCH Resource Usage CCE usage 80%

Uplink or downlink

PRB usage < 90%

Set PDCCH Symbol

Number Adjust Switch to On.

Uplink or downlink

PRB usage 90% No handling is required.

eNodeB

resources

Connected User License

Usage

Connected

user license

usage 60%

Main-control-board

CPU usage < 60% Add licenses.

Main-control-board

CPU usage 60% Add eNodeBs.

Paging Resource Usage

Percentage of paging messages

received on the S1 interface 60% or number of paging messages 1500

Decrease the number of

cells in the tracking area

list (TAL) that the

congested cell belongs

to.

Main-Control-Board

CPU Usage

Average main-control-board CPU

usage 60% or percentage of times that the CPU usage reaches or

exceeds 85% 5%

Expand the control-plane

capacity of the eNodeB.

LBBP CPU Usage Average LBBP CPU usage 60% or percentage of times that the CPU

usage reaches or exceeds 85% 5%

Expand the user-plane

capacity of the eNodeB.

Transport Resource

Group Usage

Packet loss rate 0.05%, proportion of average transmission rate to

configured bandwidth 80%, or proportion of maximum transmission

rate to configured bandwidth 90%

Expand the bandwidth of

the transport resource

group.

Ethernet Port Traffic Proportion of average transmission

rate to allocated bandwidth 70% or Proportion of maximum transmission

rate to allocated bandwidth 85%

Expand the eNodeB

transmission capacity.

2.2 Downlink User Perception

2.2.1 Monitoring Principles

Growing traffic leads to a continuous increase in PRB usage. When the PRB usage

approaches to 100%, user-perceived rates will decrease. As downlink is a major concern in an

LTE network, this document describes only how to monitor downlink user perception. The

monitoring principles also apply to uplink.




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2.2.2 Monitoring Methods

The following items are used in monitoring this case:

Downlink PRB usage L.ChMeas.PRB.DL.Used.Avg/L.ChMeas.PRB.DL.Avail x 100%

Downlink user-perceived rate (Mbit/s) = L.Thrp.bits.DL/L.Thrp.Time.DL/1000

where

L.ChMeas.PRB.DL.Used.Avg indicates the average number of used downlink PRBs.

L.ChMeas.PRB.DL.Avail indicates the number of available downlink PRBs.

L.Thrp.bits.DL indicates the total throughput of downlink data transmitted at the PDCP

layer in a cell.

L.Thrp.Time.DL indicates the duration for transmitting downlink data at the PDCP layer

in a cell.

2.2.3 Suggested Measures

Add carriers or eNodeBs if both of the following conditions are met:

Downlink PRB usage 70%

Downlink user-perceived rate < a user-defined threshold (default value: 2 Mbit/s)

2.3 PRACH Resource Usage


The PRACH transmits preambles during random access procedures.

If the number of contention-based random access attempts in a second reaches or exceeds N,

the preamble conflict probability and access delay increase. The values of N are determined during preamble design, considering factors such as that the preamble conflict probability

should be less than 1%.

If more than 100 non-contention-based random access attempts are initiated per second,

dedicated preambles will become insufficient and the eNodeB will instruct the UE to initiate

contention-based random access instead, increasing the access delay for the UE. In handover

scenarios, the handover procedure is prolonged.



Random preamble usage = (L.RA.GrpA.Att + L.RA.GrpB.Att)/3600/N x 100%

Dedicated preamble usage = L.RA.Dedicate.Att/3600/100 x 100%

where

L.RA.GrpA.Att indicates the number of times that random preambles in group A are

received.

L.RA.GrpB.Att indicates the number of times that random preambles in group B are

received.

L.RA.Dedicate.Att indicates the number of times that dedicated preambles are received.




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The value of N varies as follows:

If the system bandwidth is 15 MHz or 20 MHz, N is 100.

If the system bandwidth is 5 MHz or 10 MHz and the PRACH resource adjustment

algorithm is disabled, N is 50.

If the system bandwidth is 5 MHz or 10 MHz and the PRACH resource adjustment

algorithm is enabled, N is 100.

To check whether the PRACH resource adjustment algorithm is enabled, run the LST

CELLALGOSWITCH command to query the value of the RachAlgoSwitch.


You are advised to take the following measures:

If the random preamble usage reaches or exceeds 75% for X days (three days by default)

in a week, enable the adaptive backoff function by running the following command to

help reduce the peak RACH load and average access delay:

MOD CELLALGOSWITCH: LocalCellId=x, RachAlgoSwitch=BackOffSwitch-1;

If the system bandwidth is 5 MHz or 10 MHz, it is good practice to enable the PRACH

resource adjustment algorithm by running the following command:

MOD CELLALGOSWITCH: LocalCellId=x,RachAlgoSwitch=RachAdjSwitch-1;

If the dedicated preamble usage reaches or exceeds 75% for X days (three days by

default) in a week, enable the PRACH resource adjustment algorithm and reuse of

dedicated preambles between UEs by running the following command:

MOD CELLALGOSWITCH: LocalCellId=x,RachAlgoSwitch=

RachAdjSwitch-1,RachAlgoSwitch=MaksIdxSwitch-1;

This helps reduce the probability of UEs initiating contention-based random access in the

case of dedicated preamble insufficiency and therefore helps reduce the access delay.

2.4 PDCCH Resource Usage


This capacity indicator measures the number of control channel elements (CCEs) that can be

used by the PDCCH.

In each radio frame, CCEs must be allocated to uplink and downlink UEs to be scheduled and

common control signaling. PDCCH CCEs must be properly configured and allocated to

minimize downlink control overheads as well as to ensure satisfactory user-plane throughput.

If PDCCH symbols are insufficient, CCEs may fail to be allocated to UEs to be

scheduled, which will result in a long service delay and unsatisfactory user experience.

If PDCCH symbols are excessive, which indicates that the usage of PDCCH CCEs is low,

the resources that can be used by the PDSCH decreases. This will also result in low

spectral efficiency.




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If the value of PDCCH Symbol Number Adjust Switch is On, you do not need to monitor PDCCH

resource usage. The reason is that the eNodeB automatically adjusts the number of PDCCH symbols

based on the CCE load to meet the CCE requirement while preventing excessive PDSCH resource

consumption. You can run the LST CELLPDCCHALGO command to query the setting of PDCCH

Symbol Number Adjust Switch.


The following item is used in monitoring this case:

CCE usage = (L.ChMeas.CCE.CommUsed + L.ChMeas.CCE.ULUsed +

L.ChMeas.CCE.DLUsed)/L.ChMeas.CCE.Avail x 100%

where

L.ChMeas.CCE.CommUsed indicates the number of PDCCH CCEs used for common

signaling.

L.ChMeas.CCE.ULUsed indicates the number of PDCCH CCEs used for uplink

scheduling.

L.ChMeas.CCE.DLUsed indicates the number of PDCCH CCEs used for downlink

scheduling.

L.ChMeas.CCE.Avail indicates the number of available CCEs.


Measures to be taken also depend on the PRB usage.

If the CCE usage reaches or exceeds 80% and the uplink or downlink PRB usage is less than

90% for X days (three days by default) in a week:

If the value of PDCCH Symbol Number Adjust Switch is Off, turn on the switch by

running the following command:

MOD CELLPDCCHALGO: LocalCellId=x, PdcchSymNumSwitch=ON;

If the uplink or downlink PRB usage reaches or exceeds 90%, no handling is required.

For details about uplink or downlink PRB usage, see section 2.2 "Downlink User Perception".

2.5 Connected User License Usage


The connected user license specifies the maximum permissible number of users in

RRC_CONNECTED mode. If the connected user license usage exceeds a preconfigured

threshold, users may fail to access the network.


The following item is used in monitoring this case:

Connected user license usage = L.Traffic.User.Avg/Licensed number of connected users x 100%

where




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L.Traffic.User.Avg indicates the average number of connected users in a cell.

L.Traffic.User.Avg indicates the sum of the average number of connected users in all cells under an eNodeB.

The licensed number of connected users can be queried by running the following

command:

DSP LICENSE: FUNCTIONTYPE=eNodeB;

In the command output, the value of LLT1ACTU01 in the Allocated column is the

licensed number of connected users.


Measures to be taken also depend on the main-control-board CPU usage.

If the connected user license usage reaches or exceeds 60% for X days (three days by default)

in a week, you are advised to take the following measures:

If the main-control-board CPU usage is less than 60%, increase the licensed limit.

If the main-control-board CPU usage reaches or exceeds 60%, add an eNodeB.

For details about main-control-board CPU usage, see section 2.7 "Main-Control-Board CPU

Usage."

2.6 Paging Resource Usage


The eNodeB and BTS3202E or BTS3203E LTE can process a maximum of 750 and 500

paging messages per second, respectively. If the number of paging messages exceeds that

capacity, paging messages sent from the eNodeB to UEs may be discarded, which leads to a

decrease in the call completion rate.



Percentage of paging messages received over the S1 interface =

L.Paging.S1.Rx/3600/Maximum number of paging messages that can be processed per

second x 100%

L.Paging.Dis.Num

where

L.Paging.S1.Rx indicates the number of paging messages received over the S1 interface.

L.Paging.Dis.Num indicates the number of paging messages discarded over the Uu

interface.


You are advised to decrease the number of cells in the tracking area list (TAL) that the

congested cell belongs to if either of the following conditions is met for X days (three days by default) in a week:




10

The percentage of paging messages received by the eNodeB over the S1 interface

reaches or exceeds 60%.

1500 or more paging messages from the mobility management entity (MME) to UEs are

discarded in a day.

2.7 Main-Control-Board CPU Usage


The CPU usage reflects the busy level of the eNodeB. If the main-control-board CPUs are

busy processing control plane or user plane data, signaling-related KPIs may deteriorate, and

users may experience a low access success rate, low E-RAB setup success rate, or high

service drop rate.

Operators can determine whether KPI deterioration is caused by insufficient

main-control-board CPU processing capability or poor radio conditions. The evaluation is as

follows:

If the MCS measurement and initial-transmission failure measurement indicate that the

channel quality is poor, KPI deterioration may not be caused by main-control-board CPU

overload but by deterioration in channel quality.

If the KPIs deteriorate and the main-control-board CPU usage exceeds a preconfigured

threshold, you are advised to perform capacity expansion according to section 2.7.3

"Suggested Measures."



VS.Board.CPUload.Mean

Percentage of times that the main-control-board CPU usage reaches or exceeds a

preconfigured threshold (85%) = VS.Board.CPULoad.CumulativeHighloadCount/3600 x

100%

where

VS.Board.CPUload.Mean indicates the average main-control-board CPU usage.

VS.Board.CPULoad.CumulativeHighloadCount indicates the number of times that the

main-control-board CPU usage exceeds a preconfigured threshold.


The main-control-board CPU becomes overloaded if either of the following conditions is met

for X days (three days by default) in a week:

The average main-control-board CPU usage reaches or exceeds 60%.

The percentage of times that the main-control-board CPU usage reaches or exceeds 85%

is greater than or equal to 5%.

When the main-control-board CPU is overloaded, you are advised to add an eNodeB and

connect it to the evolved packet core (EPC) through a new S1 interface.




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2.8 LBBP CPU Usage


If the eNodeB receives too much traffic volume, which is expressed either in bit/s or packet/s,

the LBBP CPU responsible for user plane processing is heavily loaded. As a result, the

eNodeB has a low RRC connection setup success rate, low E-RAB setup success rate, low

handover success rate, and high service drop rate.



VS.Board.CPUload.Mean

Percentage of times that the LBBP CPU usage reaches or exceeds a preconfigured

threshold (85%) = VS.Board.CPULoad.CumulativeHighloadCount/3600 x 100%

where

VS.Board.CPUload.Mean indicates the average LBBP CPU usage.

VS.Board.CPULoad.CumulativeHighloadCount indicates the number of times that the

LBBP CPU usage exceeds a preconfigured threshold.


The LBBP CPU becomes overloaded if either of the following conditions is met for X days (three days by default) in a week:

The average LBBP CPU usage reaches or exceeds 60%.

The percentage of times that the LBBP CPU usage reaches or exceeds 85% is greater

than or equal to 5%.

When the LBBP CPU is overloaded, you are advised to perform capacity expansion on the

eNodeB user plane as follows:

If the LBBP is an LBBPc, replace the LBBPc with an LBBPd.

Add an LBBP to share the network load, and then determine whether to move existing

cells or add new cells based on the number of UEs. The capacity expansion methods are

as follows:

If the radio resources are sufficient (that is, the usage of each type of radio resources

is lower than the threshold), move cells from the existing LBBP to the new LBBP.

If the radio resources are insufficient, set up new cells on the new LBBP.

If the eNodeB has multiple LBBPs and one of them is overloaded, move cells from the

overloaded LBBP to an LBBP with a lighter load.

LBBP load can be indicated by the following:

Average CPU usage

Percentage of times that the CPU usage reaches or exceeds a preconfigured threshold

Number of cells established on an LBBP

If the eNodeB already has a maximum of six LBBPs and more LBBPs are required, add

an eNodeB.




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2.9 Transport Resource Group Usage


A transport resource group carries a set of data streams, which can be local data or forwarded

data. Local data is classified into control plane, user plane, operation and maintenance (OM),

and IP clock data. Forwarded data is not divided into different types. If a transport resource

group is congested, it cannot transmit or forward data, which affects service provision.

A transport resource group for user plane data is a monitored object.

Figure 2-1 shows the position of transport resource group in the TCP/IP model.

Figure 2-1 The position of the transport resource group



Packet loss rate = VS.RscGroup.TxDropPkts/VS.RscGroup.TxPkts x100%

Proportion of the average transmission rate to the configured bandwidth =

VS.RscGroup.TxMeanSpeed/Bandwidth configured for the transport resource group x

100%

Proportion of the maximum transmission rate to the configured bandwidth =

VS.RscGroup.TxMaxSpeed/Bandwidth configured for the transport resource group x

100%

where

VS.RscGroup.TxDropPkts indicates the number of packets discarded because of

transmission failures of a transport resource group.

VS.RscGroup.TxPkts indicates the number of packets transmitted by a transport resource

group.

VS.RscGroup.TxMeanSpeed indicates the average transmission rate of a transport

resource group.




13

VS.RscGroup.TxMaxSpeed indicates the maximum transmission rate of a transport

resource group.

The bandwidth configured for a transport resource group can be queried by running the

following command:

DSP RSCGRP: CN=x, SRN=x, SN=x, BEAR=xx, SBT=xxxx, PT=xxx;

In the command output, the value of Tx Bandwidth is the bandwidth configured for the

transport resource group.


A transport resource group is congested if one of the following conditions is met:

The packet loss rate reaches or exceeds 0.05% for five days in a week

The proportion of the average transmission rate to the configured bandwidth reaches or

exceeds 80% for five days in a week.

The proportion of the maximum transmission rate to the configured bandwidth reaches

or exceeds 90% for two days in a week.

When a transport resource group is congested, you are advised to expand the bandwidth of the

transport resource group. The following is an example command:

MOD RSCGRP: CN=x, SRN=x, SN=x, BEAR=IP, SBT=BASE_BOARD, PT=ETH, PN=x, RSCGRPID=x, RU=x,

TXBW=xxxx, RXBW=xxxx;

If the problem persists after the bandwidth adjustment, you are advised to expand the eNodeB

bandwidth.

2.10 Ethernet Port Traffic


The Ethernet port traffic is the channel traffic at the physical layer, including uplink and

downlink traffic. The eNodeB Ethernet port traffic reflects the throughput and communication

quality of the Ethernet ports on the main control board of the eNodeB. Based on the

monitoring results, you can determine whether the transmission capacity allocated by an

operator for the S1 and X2 interfaces on the eNodeB meet the requirements for uplink and

downlink transmissions.



(Item 1) Proportion of the average uplink transmission rate to the allocated bandwidth =

VS.FEGE.TxMeanSpeed/Allocated bandwidth x 100%

(Item 2) Proportion of the maximum uplink transmission rate to the allocated bandwidth

= VS.FEGE.TxMaxSpeed/Allocated bandwidth x 100%

(Item 3) Proportion of the average downlink reception rate to the allocated bandwidth =

VS.FEGE.RxMeanSpeed/Allocated bandwidth x 100%

(Item 4) Proportion of the maximum downlink reception rate to the allocated bandwidth

= VS.FEGE.RxMaxSpeed/Allocated bandwidth x 100%

where




14

VS.FEGE.TxMeanSpeed indicates the average transmission rate of an Ethernet port.

VS.FEGE.TxMaxSpeed indicates the maximum transmission rate of an Ethernet port.

VS.FEGE.RxMeanSpeed indicates the average reception rate of an Ethernet port.

VS.FEGE.RxMaxSpeed indicates the maximum reception rate of an Ethernet port.

The allocated bandwidth can be queried by referring to Table 2-2.

Table 2-2 Allocated bandwidth

Value of LR Switch

Main Control Board Allocated Bandwidth

Disable UMPT 1 Gbit/s

LMPT For items 1 and 2: 360 Mbit/s

For items 3 and 4: 540 Mbit/s

BTS3202E board or

BTS3203E LTE board



Enable UMPT For items 1 and 2: value of UL

Committed Information Rate (Kbit/s)

For items 3 and 4: value of DL

Committed Information Rate (Kbit/s) LMPT

You can run the LST LR command to query the values of LR Switch, UL Committed

Information Rate (Kbit/s), and DL Committed Information Rate (Kbit/s).

The types of main control boards can be queried by running the following command:

DSP BRD: CN=x, SRN=x, SN=x;

In the command output, the value of Config Type is the type of the main control board.


You are advised to perform transmission capacity expansion if either of the following

conditions is met:

The proportion of the average uplink transmission rate (or downlink reception rate) to the allocated bandwidth reaches or exceeds 70% for at least five days in a week.

The allocated bandwidth is 750 Mbit/s by default. The actually allocated bandwidth can

be obtained from the operator.

The proportion of the maximum uplink transmission rate (or downlink reception rate) to

the allocated bandwidth reaches or exceeds 85% for at least two days in a week.

eRAN7.0 Capacity Monitoring Guide 3 Resource Allocation Problem Identification



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3 Resource Allocation Problem Identification

This chapter describes how to identify resource allocation problems. Network abnormalities

can be found through KPI monitoring. If a KPI is deteriorated, users can analyze the access

counters (RRC resource congestion rate and E-RAB resource congestion rate) to check

whether the deterioration is caused by resource congestion.

3.1 Resource Congestion Indicators

Resource congestion indicators (such as the RRC resource congestion rate and E-RAB

resource congestion rate) can be used to check whether the network is congested. Table 3-1

lists the counters related to KPIs.

Table 3-1 Counters related to KPIs

Performance Counter Description

L.RRC.ConnReq.Att Number of RRC Connection Request messages received

from UEs in a cell (excluding retransmitted messages)

L.RRC.ConnReq.Succ Number of RRC Connection Setup Complete messages

received from UEs in a cell

L.E-RAB.AttEst Number of E-UTRAN radio access bearer (E-RAB) setup

attempts initiated by UEs in a cell

L.E-RAB.SuccEst Number of successful E-RAB setups initiated by UEs in a

cell

L.E-RAB.AbnormRel Number of times that the eNodeB abnormally releases

E-RABs that are transmitting data in a cell

L.E-RAB.NormRel Number of times that the eNodeB normally releases

E-RABs in a cell




16

3.1.1 RRC Resource Congestion Rate

The RRC resource congestion rate is a cell-level indicator. It is calculated using the following

formula:

RRC resource congestion rate = L.RRC.SetupFail.ResFail/L.RRC.ConnReq.Att x 100%

where

L.RRC.SetupFail.ResFail indicates the number of RRC connection setup failures due to

resource allocation failures.

L.RRC.ConnReq.Att indicates the number of RRC connection setup requests.

If the RRC resource congestion rate is higher than 0.2%, KPI deterioration is caused by

resource congestion.

3.1.2 E-RAB Resource Congestion Rate

The E-RAB resource congestion rate is a cell-level indicator. It is calculated using the

following formula:

E-RAB resource congestion rate = L.E-RAB.FailEst.NoRadioRes/L.E-RAB.AttEst x 100%

where

L.E-RAB.FailEst.NoRadioRes indicates the number of E-RAB setup failures due to

radio resource insufficiency.

L.E-RAB.AttEst indicates the number of E-RAB setup attempts.

If the E-RAB resource congestion rate is higher than 0.2%, KPI deterioration is caused by

resource congestion.

3.2 Resource Allocation Problem Identification Process

Figure 3-1 shows the Resource Allocation Problem Identification Process.




17

Figure 3-1 Resource allocation problem identification process

The fault location procedure begins with the identification of abnormal KPIs, followed up by

selecting and performing a KPI analysis on the top N cells.

Cell congestion mainly results from insufficient system resources. Bottlenecks can be

detected by analyzing the access counters (RRC resource congestion rate and E-RAB resource

congestion rate).

eRAN7.0 Capacity Monitoring Guide 4 Related Counters



18

4 Related Counters Table 4-1 lists counters involved in capacity monitoring.

Table 4-1 Counters involved in capacity monitoring.

Resource Type

Counter Name Description

PRBs L.ChMeas.PRB.DL.Used.Avg Average number of used downlink PRBs

L.ChMeas.PRB.DL.Avail Number of available downlink PRBs

L.Thrp.bits.DL Total downlink traffic volume for PDCP

SDUs in a cell

L.Thrp.Time.DL Total transmit duration of downlink

PDCP SDUs in a cell

PRACH

resources

L.RA.GrpA.Att Number of times the contention

preamble in group A is received

L.RA.GrpB.Att Number of times the contention

preamble in group B is received

L.RA.Dedicate.Att Number of times the

non-contention-based preamble is

received

PDCCH

resources

L.ChMeas.CCE.CommUsed Number of PDCCH CCEs used for

common DCI

L.ChMeas.CCE.ULUsed Number of PDCCH CCEs used for

uplink DCI

L.ChMeas.CCE.DLUsed Number of PDCCH CCEs used for

downlink DCI

L.ChMeas.CCE.Avail Number of available CCEs

Connected

user

L.Traffic.User.Avg Average number of users in a cell

Paging

resources L.Paging.S1.Rx Number of received paging messages

over the S1 interface in a cell

eRAN7.0 Capacity Monitoring Guide 4 Related Counters



19

Resource Type

Counter Name Description

L.Paging.Dis.Num Number of discarded paging messages

from the MME to UEs due to flow

control in a cell

Board CPU

resources

VS.Board.CPUload.Mean Average Board CPU Usage

VS.Board.CPULoad.Cumulative

HighloadCount

Number of Times that the CPU Usage of

Boards Exceeds the Preconfigured

Threshold

Transport

resource

groups

VS.RscGroup.TxPkts Number of packets successfully

transmitted by the resource group

VS.RscGroup.TxDropPkts Number of packets discarded by the

resource group due to transmission

failures

VS.RscGroup.TxMaxSpeed Maximum transmit rate of the resource

group

VS.RscGroup.TxMeanSpeed Average transmit rate of the resource

group

Ethernet ports VS.FEGE.TxMaxSpeed Maximum transmit rate on the Ethernet

port

VS.FEGE.TxMeanSpeed Average transmit rate on the Ethernet

port

VS.FEGE.RxMaxSpeed Maximum receive rate on the Ethernet

port

VS.FEGE.RxMeanSpeed Average receive rate on the Ethernet port

About This DocumentDraft A (2014-1-20)

1 Overview1.1 Network ResourcesTable 1-1 Network resources

1.2 Capacity Monitoring Methods

2 Capacity Monitoring2.1 IntroductionTable 2-1 Types of resources to be monitored, thresholds, and handling suggestions

2.2 Downlink User Perception2.2.1 Monitoring Principles2.2.2 Monitoring Methods2.2.3 Suggested Measures

2.3 PRACH Resource Usage2.3.1 Monitoring Principles2.3.2 Monitoring Methods2.3.3 Suggested Measures

2.4 PDCCH Resource Usage2.4.1 Monitoring Principles2.4.2 Monitoring Methods2.4.3 Suggested Measures

2.5 Connected User License Usage2.5.1 Monitoring Principles2.5.2 Monitoring Methods2.5.3 Suggested Measures

2.6 Paging Resource Usage2.6.1 Monitoring Principles2.6.2 Monitoring Methods2.6.3 Suggested Measures

2.7 Main-Control-Board CPU Usage2.7.1 Monitoring Principles2.7.2 Monitoring Methods2.7.3 Suggested Measures

2.8 LBBP CPU Usage2.8.1 Monitoring Principles2.8.2 Monitoring Methods2.8.3 Suggested Measures

2.9 Transport Resource Group Usage2.9.1 Monitoring PrinciplesFigure 2-1 The position of the transport resource group

2.9.2 Monitoring Methods2.9.3 Suggested Measures

2.10 Ethernet Port Traffic2.10.1 Monitoring Principles2.10.2 Monitoring Methods2.10.3 Suggested Measures

3 Resource Allocation Problem Identification3.1 Resource Congestion Indicators3.1.1 RRC Resource Congestion Rate3.1.2 E-RAB Resource Congestion Rate

3.2 Resource Allocation Problem Identification Process

4 Related Counters

ERAN Capacity Monitoring Guide

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