The document discusses key performance indicators (KPIs) for LTE networks. It describes KPIs related to accessibility, retainability, integrity, and mobility. Accessibility KPIs measure how successfully users can access the network, including session setup success rate, RRC connection success rate, and ERAB establishment success rate. Retainability KPIs evaluate how well services are retained once connected, such as call drop rate and ERAB drop rate. Integrity KPIs relate to throughput, including downlink and uplink throughput. Mobility KPIs cover handover success rates for different types of handovers between nodes. Formulas are provided for calculating many of the KPIs.

1. Introduction
To
LTE KPIs
Prepared by : Mradul Nagpal

2. Contents :-
 Introduction to Primary KPIs
 Accessibility KPIs
 Retainability KPIs
 Integrity KPIs
 Mobility KPIs

3. Introduction of Primary KPIs
Domain Area Node Primary KPILTERAN
Accessibility
eNB
Session Setup Success rate(%) [24 hrs.]
RRC Connection Success Rate (%) [24 hrs.]
S1 Establish Success Rate (%) [24 hrs.]
ERAB Established Success Rate(%) [24hrs.]
Retainability Call Drop Rate (%) [24hrs.]
Integrity Avg. MAC Uplink Throughput(kbps) [24hrs.]
Avg. MAC DownlinkThroughput(kbps)
Mobility LTE Handover success rate (%)
Intra eNB Handover Success Rate (%)
Inter X2 out Success rate (%)
Inter S1out Success rate (%)

4. Accessibility KPIs
 Accessibility KPIs are used to measure how
successfully user is able to access the network
 It is generally divided in 3 segments i.e., RRC*
setup, S1 setup and ERAB** setup.
*Radio Resource Control
**E-UTRAN Radio Access Bearer

6. RRC Setup Success Rate (Service)
 According to Reference, the RRC connection setup procedure is triggered by
various different causes as identified by the “establishment Cause” field in RRC
Connection Request message: emergency, high Priority Access, MT (Mobile
terminating)-Access, MO(Mobile Originating)-Signalling, and MO-Data.
 The UE sets the establishment Cause in accordance with the information
received from upper layers. Causes except mo-signaling are categorized as
service-related ones. The mo-signaling cause is a signalling-related cause. This
KPI evaluates the RRC setup success rate with service-related causes in a cell
or cluster Involved.
 The KPI is calculated based on the counters measured at eNodeB when the
eNodeB receives an RRC Connection Request from the UE.
 The number of RRC Connection attempts is collected by the eNodeB at
measurement point A and the number of successful RRC connection is
counted at measurement point C.

7. Measurement point for RRC connection setup

8. RRC setup success rate (service)
KPI Name
Measurement
scope
RRC Setup Success Rate (service)
Cell / Cluster
Formula
RRCS_SRservice = RRC Connection Success
Associated
Counters
Unit Percentage (%)
RRC Connection Attempts
X 100

9. RRC Setup Success Rate (Signalling)
 This KPI evaluates the RRC setup success rate of the
signalling-related cause (mo-signaling) in a cell or a
cluster.
 Like the RRC Setup Success Rate (service), this KPI is
used to calculate the RRC setup success rate only when
the “establishment Cause” field is set to mo-signaling in
a cell or a cluster.

10. KPI Name
Measurement
scope
RRC Setup Success Rate (Signalling)
Cell / Cluster
Formula
RRCS_SRservice = RRC Connection Success
Associated
Counters
Unit Percentage (%)
RRC Connection Attempts
X 100

11. ERAB Setup Success Rate (All)
Number of ERAB Connection setup attempts is collected by the eNodeB at
measurement point A and the number of successful ERAB connections is
counted at measurement point B, as shown in Figures. Note that the eNodeB
needs to specify the Quality of Service (QoS) Class Identifier (QCI) forVoIP in
the ERAB setup message.
The voice service can be identified by the QoS information, in particular the
QCI in the ERAB Setup Request message. In general, QCI 1 is assigned to the
voice service.
This KPI can be used to evaluate the ERAB setup success rate of all services
including theVoIP service in a cell or a cluster.This KPI is calculated based on
the counters (both the ERAB setup attempts (All) and the successful ERAB
setup (All) counters) measured at the eNodeB.

12. Measurement point for MME-initiated ERAB setup

13. Measurement point for UE-triggered ERAB setup

14. ERAB setup success rate.
KPI Name ERAB Setup Success Rate
Measurement
Scope
Cell / Cluster
Formula
Associated
Counter
ERABS_SR =
Unit Percentage (%)
Success ERABSetup
Attempt ERABSetup
X 100

15. Call Setup Success Rate
 This KPI can be used to evaluate the call setup success rate of all
services including the VoIP service in a cell or a cluster. This KPI is
calculated based on the KPI of RRC Setup Success Rate (Service)
and the KPI of ERAB Setup Success Rate (All).
 The KPI is calculated base on multiplying the KPI of RRC Setup
Success Rate (Service) and the KPI of ERAB Setup Success Rate
(All)

16. Call Setup Success Rate
KPI Name Call Setup Success Rate
Measurement
Scope
Cell / Cluster
Formula
Associated
Counter
CSSR =
Unit Percentage (%)
RRCConnectionSuccess
X
RRCConnectionAttempt
ERABSetupSuccess
X100
ERABSetupAttempt

17. Retainability KPIs
 Retainability KPIs are used to evaluate the network capability to
retain services requested by a user for a desired duration once the user
is connected to the services. These counters can be calculated per cell
or per cluster. The KPIs at the cluster level can be calculated by
aggregating all the cell counters. Retainability KPIs are important in
evaluating whether the system can maintain the service quality at
certain level.
 The call drop statistics are on the calls that are connected
successfully but abnormally dropped due to eNB failure, by the MME
or any other reason.
Call Drop rate(%)
ERAB Drop Rate (%)

18. Calculations
KPI Name Formula
Call Drop Rate (%) [Call Drop(All type id sum) / (EstabInitSuccNbr+
InterX2InSucc + InterS1InSucc)] * 100
ERAB Drop Rate(%) RelActive/ (EstabInitSuccNbr+ EstabAddSuccNbr) * 100

19. Integrity KPIs
 These statistics collects data for cell throughput of downlink/uplink transport
blocks the ENB MAC allocated to UE.
KPI Name Formula
Cell MAC Downlink Effective
Throughput (kbps)
[(AirMacByteDl*8)/AirMacTtiDl]*1000
Cell MAC Uplink EffectiveThroughput
(kbps)
[(AirMacByteUl* 8)/AirMacTtiUl]*1000

20. Mobility KPIs
 Mobility KPIs includes Inter ENB Handover, X2 &
S1 handover KPIs.
 Overall Handover success rate is the combination
of all 3 types of HO procedures.
 X2 & S1 handover will depends on the
configuration of the interfaces.

21. Calculations

22. Intra eNB Handover Success Rate (%)
 Intra ENB HO is between different cells of same
ENBs.
 All the Handover procedures are divided in 2
phases, Preparation phase & Execution phase.

25. Inter X2 Out Success Rate (%)
X2 HO is between 2 cells of different ENBs, which are
connected with X2 interface.

26. Inter S1 Out Success Rate (%)
S1 HO is between 2 cells of different ENBs, which are not
connected with X2 interface, in actual network it will be
between inter MME mainly.