Joint AOD and CFO estimation in wireless sensor networks localization system

Self-localization system of wireless sensor networks based on angle of departure (AOD) is studied in this paper. In AOD model, anchor node with multi-antenna transmits orthogonal pilot signals to sensor node with single antenna, which entitles the sensor node to function as equipping multi-antenna. Given that the limited number of antenna at anchor nodes will result in degree of freedom (DOF) deficiency at sensor node when dealing with more multipath components (MPC), we adopt a novel method without requiring extra antennas. The proposed algorithm simultaneously includes the oscillator mismatch between anchor node and sensor node, i.e., carrier frequency offset (CFO). With the aid of anchor´s movement and CFO, the equivalent antenna array at sensor node is expended by synthetic aperture procedure to a much larger one, which subsequently improve the estimation ability to MPCs. In addition, the close-form solutions of CFO and AOD are also derived. The effectiveness and performance of proposed algorithm are demonstrated by numerical simulations.