4
Key Performance Indicators and Measurements for LTE Radio Network Optimization
This chapter describes how the different interfaces of the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) can be monitored and which measurement equipment can be used. It also outlines which important performance parameters are required to troubleshoot and optimize the network and a set of counter-based KPIs (Key Performance Indicators) is proposed to check the performance of the most essential network functions.
4.1 Monitoring Solutions for LTE Interfaces
The following sections describe approaches of monitoring the LTE interfaces from the air interface through core network (EPC) interfaces. All fixed line interfaces are IP-based protocol stacks, thus interfaces widely use a physical and link layer predominantly used for IP, like Ethernet.
Although legacy ATM (Asynchronous Transfer Mode) networks are technically able to transport IP-type traffic, capacity constraints should be kept in mind (see Section 4.1.5).
4.1.1 Monitoring the Air Interface (Uu)
The main factor influencing the performance increase is the higher complexity of the air interface. This results in a need to monitor the protocols and procedures on the LTE air interface, because on fixed line interfaces nothing of these required factors is seen any more as interesting protocols and procedures are only “seen” on the air interface (Section 1.8). Instead of UMTS, the Iub interface between NodeBs and RNCs carries each frame ...
