https://www.sharetechnote.com/html/Handbook_LTE_Timer_RRC.html
and
3GPP TS 36.331 5.3.11 Radio link failure related actions
3GPP TS 36.331 5.3.7 RRC connection re-establishment
3GPP TS 36.213 4.2.1 Radio link monitoring
3GPP TS 36.133 7.6 Radio Link Monitoring
Once things go bad in your phone and it gets out-of-sync (after N310 times), it starts T310 to wait for PHY get back in shape and return to in-sync.
If PHY doesn’t recover and T310 expires, the UE starts T311 in order to reselect into another cell, or even the same cell if in the meantime RF gets back to acceptable ranges. T311 is a supervision timer for the cell selection procedure after a OoS scenario.
If before T311 expires the UE finds a suitable cell, it stops T311, starts T301, send RRCConnectionReestablishmentRequest and wait for the eNodeB response. The T301 is a supervision timer for the RRCConnectionReestablishment procedure.
If T311 expires before the UE finds a suitable cell, or the T301 expires before the RRCConnectionReestablishment, the UE goes to RRC_IDLE.
If success is achieved in the Reestablishment procedure, UE happily goes back to RRC_CONNECTED.