A device and method for power optimization for a user equipment (UE) without neighbor cell measurement configuration. The UE may be configured with Connected Discontinuous Reception (C-DRX) functionality including a cycle with an onDuration. The UE may be configured with carrier aggregation (CA) in the unlicensed spectrum including a reference signal (DRS) monitoring timing configuration (DMTC) occasion that occurs outside of the onDuration. The UE determines at least one subframe of the onDuration for the UE to utilize an active mode of processing related to performing measurements corresponding to a cell utilizing the unlicensed spectrum. The UE determines to utilize a sleep mode of processing related to performing the measurements during the DMTC occasion based on detecting a first downlink signal transmitted by the cell during the at least one subframe of the onDuration.