The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Embodiments herein disclose methods and systems for an unlicensed carrier to be added in LTE-U based communication networks by performing measurements for the unlicensed carrier as in legacy LTE for the addition of a licensed carrier, while ensuring that the UE knows when to measure the unlicensed channels.