BlueVoice: Voice communications over Bluetooth Low Energy in the Internet of Things scenario.

Bluetooth Low Energy (Bluetooth LE) is a key technology in the envisioned Internet of Things (IoT) scenario. In fact, its extremely low-power characteristics make it one of the most suitable solutions to enable wireless communications among battery powered IoT objects ubiquitously deployed in the field with the aim of building smart environments. Although Bluetooth LE specification targets a specific set of applications mainly devoted to monitoring purposes, innovative solutions can lead to the adoption of such technology in different applications, such as multimedia streaming, allowing IoT objects to exploit new functionalities. In this direction this article presents BlueVoice, an application targeted to Bluetooth LE devices to enable speech streaming services. In the article BlueVoice is presented by first detailing the services set extension needed to support the new envisioned multimedia service, then a description of application choices is given, followed by an evaluation of its performance in real IoT objects. Thanks to the selected speech encoding technique, connection design choices and packetization strategies, BlueVoice application requires a communication bandwidth of 64.3 kbps to transmit audio at 16 kHz in ADPCM format. BlueVoice performance has been evaluated in terms of power consumption, memory and processing requirements, showing feasibility of the developed solution in resource constrained devices, thus confirming the correct choices in the application design. The set of performance information obtained show that BlueVoice is a viable solution to enable speech communications in ubiquitous wireless IoT nodes based on the Bluetooth LE technology.