A review and analysis of scientific papers published to date on various aspects of 6G is presented. The emphasis is on physical layer technologies, since they are the ones that largely form the basis and determine the potential of the future system. These include multiple access, multi-user multi-antenna systems, reconfigurable reflective surfaces, and modulation and channel coding techniques. In addition, promising application scenarios, new services and services, predicted requirements, concepts of 6G network architecture, the role of artificial intelligence and machine learning, as well as new frequency ranges are considered.