Accessibility: RRC connection setup success rate

Accessibility - In providing services to end-users, the first step UE performs is to get access to the network. It is imperative to provide services to users whenever requested and the first key performance indictor that comes first into picture to analyse it is RRC connection setup success rate.

Radio resource control (RRC) protocol exists at IP level (layer 3) between UE and eNB. The major functions of the RRC protocol include connection establishment and release functions, broadcast of system information, radio bearer establishment, reconfiguration/release, RRC connection mobility procedures, paging notification and outer loop power control.

From OSS reports, RRC failure reasons can be identified and accordingly plan of action to mitigate it is mechanized. Key reasons for low RRC success rate are as follow –

• Failure in Radio layer – Coverage/Quality/Interference
• Failure due to unavailability of resources – Radio/MME/Transport
• Maximum number of RRC connections achieved
• Failure due to other reasons – HW/SW/VSWR/Ant line etc.

Note - There can be few other reasons for RRC failure but majority belongs to above mentioned ones.