A base station is provided. The base station transmits multiple data in a first subframe, receives response signals corresponding to the multiple data, determines a ratio of negative acknowledge (NACK) signals to the response signals, and adjusts or maintains a contention window based on the determined ratio. The present disclosure relates to communication schemes for combining 5th-generation (5G) communication systems with internet of things (IoT) technology to support higher data transmission rate as post-4th-generation (post-4G) systems and systems for the same. The present disclosure may be used in intelligent services (e.g., smart home, smart building, smart city, smart car, or connected car, health-care, digital education, retail business, security and safety-related services, etc.) based on the 5G communication technology and IoT-related techniques.