The 3GPP Long Term Evolution (LTE) is considered as a dominant future cellular wireless technology in terms of performance and user experience. With technological advancement of the wireless networks, dependencies and business impact of the mobile network services have increased phenomenally. It is, therefore, crucial to address the issues regarding network infrastructure or service failure. In this thesis, a self-healing solution is presented for the LTE Evolved Packet Core (EPC) with a view to maintaining service continuity in the event of core network elements - the MME and S-GW failures. The core network element failures have significant impact on a larger number of subscribers in comparison to the access network element failures. In the proposed self-healing scheme, the restoration mechanisms and associate failover recovery procedures with regards to service survivability are described in details from the LTE network and protocol perspective. This thesis studies two different self-healing approaches - the centralized active-backup and distributed active-active and conducts simulation for each approach in various failure scenarios. The performances of each of these scenarios are evaluated in terms of service restoration time, throughput, EPS (Evolved Packet System) bearer delay etc. The results show that the proposed self-healing system can ensure service continuity at a certain level if resources are properly provisioned. And in terms of restoration delay, in general, the active-backup configuration performs better than the active-active configuration. The thesis presents analytical and simulation methods to estimate signaling message overhead at the LTE EPC that arises due to the recovery process. It also analyzes the bandwidth requirements of the signaling traffic that is incurred by the other operational procedures of the self-healing scheme and their ramification to the LTE core network. / UOIT

The thesis is focused on the description of LTE system in terms of signaling on interfaces of LTE and EPC subsystems, such as UE initial network connection. The next section describes the types of diagnostic methods for mobile networks using OSS, drive testing and flow analysis. The thesis also aims at description of key performance indicators (RSRP, RSSI, etc.) and the proposal for measuring of the LTE network physical layer and the data transmission speed.

The thesis is focused on the description of LTE system in terms of signaling on interfaces of LTE and EPC subsystems, such as UE initial network connection. The next section describes the types of diagnostic methods for mobile networks using OSS, drive testing and flow analysis. The thesis also aims at description of key performance indicators (independent service QoS parameters and the KPI for the radio part of the network). Part of the network measurement includes a description of the driver settings and views for analysis. It is also described the implementation of measuring and evaluating the results.