Device Discovery Approaches in D2D Communication: A Survey

As the world is moving forward to the Fifth Generation (5G) of wireless technology, the demand for efficient communication techniques has also increased. 5G provides a far higher level of performance than previous generations of wireless communication in terms of low latency, increased throughput, and increased spectral efficiency. In 5G, some companion technologies have been added to strengthen the communication efficiency among the users. Device-to-Device(D2D) communication is one of these technologies to be used for modern cellular networks like 5G. D2D technology allows devices to communicate with each other without the assistance of a base station. The primary benefits of D2D communication include increased spectrum, energy efficiency, reduced transmission delay, and improved system throughput. Along with these benefits, several technical challenges include device discovery, resource allocation, mode selection, interference management, privacy, and security. In this paper, we discuss one of the challenges and the primary aspect of D2D communication, i.e., Device Discovery. The device discovery process starts when the devices transmit a discovery signal to an intermediate device to enhance the communication process by connecting with that device. Finding a potential intermediate device that will not disrupt the communication channel can sometimes become challenging. The device discovery process cannot be overlooked as it is an important step that is required before the establishment of D2D communication as well as during the communication process. In other words, device discovery is one of the key building blocks of D2D-based networks. This paper thoroughly reviews most of the important device discovery techniques for D2D communication.