Reliable and accurate localization awareness is of great importance for the distributed multi-agent system (DMAS). Instead of global information, measurements only between neighbors pose locatability and accuracy challenges for distributed systems, which leads to the development and application of relative localization. In this paper, we put forward a backbone-listener localization scheme for the D-MAS. Agents switch backbone-listener modes through a node selection strategy. Position and orientation angle of agents are jointly estimated by range and angle information fusion. A distributed multidimensional scaling method is proposed for backbone agents to maintain the topology estimation. And listener agents ensure the localization capacity through a least square range and angle fusion algorithm. Extensive simulation and real-world experiments validate that our method achieves decimeter-level accuracy relative localization.

The position and time of mobile agents are essential information for many wireless network applications. In this paper, we propose a single-anchor localization and synchronization scheme of full-duplex (FD) agents in the line-of-sight scenario, where the anchor is equipped with an antenna array. The agents perform inter-node ranging using the FD radios, while the anchor only receives signals transmitted from the agents. We derive the Cramér-Rao lower bounds for the agent positions and clock offsets based on the frames received by the agents and anchor. In particular, the Fisher information matrix for the positions and clock offsets can be decomposed into the information from the measurements of the arrival angles and arrival times. Then, we design the channel estimation algorithm to obtain the arrival angles, arrival times, and signal-to-noise ratios, based on which we further develop the network localization and synchronization algorithms to obtain the agent positions and clock offsets. The simulation results illustrate the performance of our proposed scheme and algorithms.

Both localization and synchronization of mobile nodes are of fundamental importance for wireless networks. With the emergence of full-duplex (FD) communication technology, inter-node distances and clock offsets among a set of nodes can be simultaneously obtained through only two frames of communications, thus significantly improving the efficiency of node localization and synchronization. In this paper, we propose a localization and synchronization scheme using FD radios, and characterize its performance. Our study derives the Cramér-Rao lower bounds (CRLBs) for inter-node distances and clock offsets, the former of which can be translated into the estimation error bounds for localization. Comparison to conventional frequency division duplex (FDD) or time division duplex (TDD) demonstrates the high efficiency of localization and synchronization using FD radios. Our results reveal the potential of full-duplex technology beyond data communications in future wireless networks.