Human activity recognition (HAR) has an important role in various areas of research, including security, health, daily activity, elderly, energy consumption in the smart building, etc. Most survey papers on HAR discuss single activity recognition. This study explained the research survey on group activity recognition (GAR) and linked it to the advancement of IoT technology in smart building. Object usage sensor activity recognition (OUAR) has a higher chance than video and wearable sensor-based because of its compatibility with the activity recognition system while preserving user privacy and convenience. OUAR can benefit HAR systems when IoT is used (all devices and sensors are integrated into the Internet). This is in line with the advancement of smart building. Also, many data sensors in AR and smart building systems when using OUAR can integrate big data to generate HAR systems in future smart buildings.
