Two-Way Communication Protocol using Bluetooth Low Energy Advertisement Frames

Abstract

Bluetooth Low Energy (BLE) is a wireless personal area network technology designed to provide low-power connectivity to smartphones and wearable devices. To transmit bidirectional data, devices must first discover each other and then start a pairing process. Usually, the pairing process requires manual intervention that might result in undesirable user experiences. If security and privacy requirements allow, communication sessions could be limited to the advertisement channels only, without pairing the devices. Further, the use of only advertisement channels without pairing devices enables scenarios in which different radio systems can also join the communication. For example, the nRF24L01+ radio system can be programmed to communicate using the advertisement channels defined by BLE. This is relevant because the nRF24L01+ radio system is a popular technology for the Internet-of-Things and for location-based services with wearable devices in smart cities. This paper evaluates a two-way communication protocol between the nRF24L01+ and BLE devices, using only advertisement frames. We show a practical protocol implementation and use an experimental testbed to evaluate its performance. The evaluation shows that it is possible to build a simple and reliable communication protocol that works in both directions.