is considered as failure and UE detects radio link failure and triggers RRC connection re- establishment procedure as shown in Figure 12.30. Minimizing this type of re-establishment can be done by random access setup success rate improvement parameters as shown in Section 12.4.1. Also PUCCH power control should be set to compensate max pathloss while minimizing the inter-cell interference to avoid SRI being sent using random access procedure (due to the poor coverage of PUCCH). 12.5.3 eNodeB-triggered RRC Connection Re-establishments The eNodeB has triggers for radio link problem detection and in case any of those link monitors detect the problem, the eNodeB will wait for radio link recovery until defined timer expires without any RRC connection re-establishment request received from the UE. Radio link problem detection is typically as below: UL PUSCH DTX detection: After the uplink capacity grant is given there is nothing received on the allocated PUSCH resources Certain amount of consecutive periodical CQI reports not received on PUCCH or PUSCH No uplink ACK/NACK received but only DTX for downlink data transmissions LTE Key Performance Indicator Optimization No allocated preamble received as a response to PDCCH order No allocated sounding reference signal (SRS) received but instead DTX detected on allo- cated resources Each of the above-mentioned radio link problem triggers has its own controlling parameters which impact on the radio link problem detection and therefore start of radio link recovery timer. In case of expiry of the radio link recovery timer of the RRC connection, all E-RABs and S1 connection are released. The eNodeB radio link recovery timer should be longer than T310 + T311 SO that the UE can perform RRC connection re-establishment to the source cell or to any other cell before connection is considered to be dropped. Figure 12.31 shows the impact of the radio link recovery timer increase for a cluster (timer change implemented at day 10). Also possible UE context fetching time should be included