Full Duplex DD for In-Band D2D Communication

Abstract

Device to device (D2D) communication is a candidate technology to ascertain the 5G wireless system. To implement the D2D communication in an in-band cellular network, device discovery (DD) is a primary and critical task. A positioning reference signal has been incorporated to discover the device in the 4G-LTE system, but the DD is still a challenge due to the non-line of sight (NLOS) and scattering environment. The discovery signal distorts due to these challenges at both device and base station ends. Along with NLOS and scattering, the practical issues for the DD are the latency, precision, and energy efficiency. They need special attention to achieve, because of the random mobility of the devices. A full-duplex (FD) DD procedure is suggested in which the discovery signal is transmitted from both ends. To solve these challenges and attains effective DD procedure, the log-likelihood maximization and estimation based algorithm is applied on the FD signal from three base stations (triangulation). It incorporates the FD and triangulation-based data, NLOS characteristics, elliptical scattering model, and MUSIC spectrum information for direction of arrival. It reduces the 40% energy consumption by linear estimation and achieves maximum discovery at 220 iterations. It also reduces the average discovery (position) error 52 cm according to KPI of 5G. The proposed system is a comprehensive work managing fundamental issues developing DD in practical situations: directionality, impediment forces, environment supervision, and base station coordination.