Numerical method for estimation of feasibility of device-to-device communication in LTE

Abstract

Device-to-device (D2D) communication is a promising new feature in LTE-Advanced networks. In conventional cellular networks, devices can only communicate with the base station via uplink or downlink paths. It fails to meet the ever-increasing demand of proximity-based social/commercial services and applications. The innovative architecture of D2D under laying LTE networks is therefore brought up to enable efficient discovery and communication between proximate devices. With D2D capability, devices in physical proximity could be able to discover each other using LTE radio technology and to communicate with each other via a direct data path. Apart from the general social/commercial use, the LTE D2D is further expected to address Public Safety communities. This thesis is concerned with the numerical method for estimation of feasibility of device-to-device communication in LTE. Design requirements and choices in physical and MAC layer functions to support D2D discovery and communication under laying LTE networks are analyzed. In addition, a centralized scheduling strategy in base station is proposed to coordinate D2D data communication operating in LTE FDD downlink spectrum. The scheduling strategy combines multiple techniques, including mode selection, resource and power allocation, to jointly achieve an overall user performance improvement in a cell. Finally the performances of D2D data communication under laying LTE system are calibrated in a multi-link scenario via system-level simulation. D2D data communication is scheduled by base station with the proposed scheduling method and the hybrid D2D and cellular system is compared to pure cellular system, in which all traffics must go through base station. The simulation results show that considerable performance gains are achieved by enabling direct D2D data paths to replace conventional uplink-plus-downlink data paths for local data traffic between proximate devices, and by allowing non-orthogonal re- source reuse between D2D and cellular downlink transmission. The initial tests demonstrate that the proposed scheduling method successfully mitigates interferences result- ing from the intra-cell resource reuse.