(事前公開アブストラクト) Virtual grid is new energy solution leveraging portable batteries for off-grid area. For safety, batteries need to be controlled by management system remotely. To realize the batteries' remote control, we expanded Crowd Tracking, a mechanism that a proxy receives BLE beacon, to "Crowd Tracing". In this presentation, we focused on discussing a method of Crowd Tracing with publish/subscribe model. Whereas, we proposed one particular method with Eddystone-URL and MQTT protocol, and discussed possibility of the objective. In conclusion, we revealed a device non-connected to Internet can receive a message from a remote device via a third party's smartphone given the subscribing topic.