An operating method of a terminal performing a cell search using first and second memories for buffering input samples includes detecting a first primary synchronization signal (PSS) group from a first input sample group while buffering the first input sample group in the first memory in a first interval. While buffering a second input sample group in the second memory in a second interval following the first interval, the method detects a second PSS group from the second input sample group, and a first secondary synchronization signal (SSS) group corresponding to the first PSS group from the first input sample group. While buffering a third input sample group in the first memory in a third interval following the second interval, the method detects a third PSS group from the third input sample group, and a second SSS group corresponding to the second PSS group from the second input sample group.