An operation method of a terminal in a communication system may comprise: obtaining a plurality of serving beam measurement values by performing measurement on a plurality of serving beams; identifying a minimum measurement value among the plurality of serving beam measurement values; obtaining a plurality of beam measurement values by performing measurement on a plurality of beams received from a plurality of base stations included in the communication system; determining whether a first condition is satisfied, the first condition being defined based on a result of comparison between the plurality of beam measurement values and a sum of the minimum measurement value and a first offset; and in response to determining that the first condition satisfied, performing communication with at least part of the plurality of serving base stations and a first base station forming a first beam satisfying the first condition.