LTE Accessibility KPI and Counters Mapping.​

1. RRC Setup Success Rate (Service)

The RRC (Radio Resource Control) setup procedure in LTE is initiated for various reasons, identified by the establishmentCause field in the RRCConnectionRequest message. These reasons include:

• emergency
• highPriorityAccess
• mt-Access (mobile terminating access)
• mo-Signaling (mobile originating signaling)
• mo-Data (mobile originating data)
• delayTolerantAccess-v1020

The UE (User Equipment) sets the establishmentCause and this is received by the eNodeB (Evolved Node B). For KPI (Key Performance Indicator) purposes, causes other than mo-Signaling are categorized as service-related, while mo-Signaling is categorized as signal-related.

The RRC Setup Success Rate (Service) KPI evaluates the success rate of RRC setups with service-related causes in a specific cell or cluster.

$RRC\_SS{R}_{Service}=\frac{RRC\_ConnectionSucces{s}_{Service}}{RRC\_ConnectionSucces{s}_{Attempt}}\times 100$

RRC Setup Success Rate (Signal)

This KPI evaluates the RRC setup success rate specifically for the signal-related cause (mo-Signaling) in a cell or cluster.

These two KPIs help in assessing the performance of the RRC setup process by distinguishing between service-related and signal-related causes, providing valuable insights for network optimization.

$RRC\_SS{R}_{Signal}=\frac{RRC\_ConnectionSucces{s}_{Signal}}{RRC\_ConnectionSucces{s}_{Signal}}\times 100$

2. Counter Mapping for RRC SSR.

LTE-SAE QoS Class Identifier

In LTE, there are nine QCIs (QoS Class Identifiers) defined by 3GPP TS 23.203. Each QCI has its own QoS requirements, and each E-RAB (Evolved Radio Access Bearer) is assigned a QCI attribute.

QCI	Resource type.	Priority	Packet delay budget (ms).	Packet error loss rate.	Example services.
1	GBR	2	100	10−2	Conversational voice.
2	GBR	4	150	10−3	Conversational video (live streaming)
3	GBR	5	300	10−6	Non-conversational video (buffered streaming).
4	GBR	3	50	10−3	Real time gaming.
5	Non-GBR	1	100	10−6	IMS signalling.
6	Non-GBR	7	100	10−3	Voice, video (live streaming), interactive gaming.
7	Non-GBR	6	300	10−6	Video (buffered streaming).
8	Non-GBR	8	300	10−6	TCP-based (e.g. WWW, e-mail) chat, FTP, p2p file sharing, progressive video, etc.
9	Non-GBR	9	300	10−6

3. ERAB Setup Success Rate.

VoIP ERAB Setup Success Rate: This KPI measures the success rate of ERAB setups for VoIP services (QCI 1) in a specific cell or cluster. The formula for calculating this KPI is:

$VoIP\_ERAB\_SSR=\frac{VoIP\_ERAB\_SetupSuccess}{VoIP\_ERAB\_SetupAttempt}\times 100\%$

ERAB Setup Success Rate (All): This KPI measures the success rate of ERAB setups for all services, including VoIP, in a specific cell or cluster. The formula for this KPI is:

$ERAB\_SSR\left(All\right)=\frac{ERAB\_SetupSuccess}{ERAB\_SetupAttempt}\times 100\%$

4. Counter Mapping for ERAB SSR.

Call Setup Success Rate.

VoIP Call Setup Success Rate (VoIP CSSR): This KPI evaluates the success rate of the entire call setup procedure for VoIP services (QCI 1) in a cell or cluster. This procedure includes three main phases: RRC setup, S1 signaling connection establishment, and VoIP E-RAB setup. The formula for calculating VoIP CSSR is:

$VoIP\_CSSR=\frac{RRC\_ConnectionSucces{s}_{Service} }{RRC\_ConnectionAttemp{t}_{Service}}\times \frac{S1SIGConnectionEstablishSuccess}{S1SIGConnectionEstablishAttempt}\times \frac{VoIP\_ERAB\_SetupSuccess}{VoIP\_ERAB\_SetupAttempt}\times 100$

Call Setup Success Rate (All): This KPI measures the call setup success rate for all services, including VoIP, in a cell or cluster. It also includes the three main phases: RRC setup, S1 signaling connection establishment, and service E-RAB setup. The formula for calculating CSSR (All)

$CSSR\left(All\right)=\frac{RRC\_ConnectionSucces{s}_{Service} }{RRC\_ConnectionAttemp{t}_{Service}}\times \frac{S1SIGConnectionEstablishSuccess}{S1SIGConnectionEstablishAttempt}\times \frac{ERAB\_SetupSuccess}{ERAB\_SetupAttempt}\times 100$

These KPIs are critical for evaluating and optimizing the performance and reliability of LTE networks, ensuring high-quality service for end users.

Counter Mapping for CSSR.