*Proceeding Paper* **Design, Implementation and Validation of a Bluetooth 5 Real-Time Monitoring System for Large Indoor Environments †**

**Iván Froiz-Míguez 1,2,\*, Paula Fraga-Lamas 1,2 and Tiago M. Fernández-Caramés 1,2**


**Abstract:** The progress of LPWAN technologies in recent years has increased their use in various types of environments as well as increased the applications in which they are used. However, due to the duty cycle limitations of license-free based technologies, they have a considerable limitation for applications with frequent data transmission or real-time data. In this regard, technologies working in the 2.4 GHz band are a compelling option to consider but their main problem concerns their limited range. Fortunately, the new Bluetooth 5 standard has a new feature (Long Range mode) that is especially useful in long distance or large indoor environments. This paper describes a practical study on this new technology for indoor environments. The performed experiments evaluate reception range, communications quality, channel occupancy, response times, and power consumption. The obtained results indicate that a three-floor building of more than 4200 m2 may be covered with a stable signal with only two Bluetooth 5 nodes.

**Keywords:** Bluetooth 5; LPWAN; IoT; LE coded; real-time monitoring

**1. Introduction**

LPWAN technologies have undergone constant evolution in the last years and have become widespread in many environments. However, they do have limitations in certain types of applications, one of which concerns the restrictions on transmission due to the duty cycle. In this aspect, 2.4 GHz license-exempt ISM-band technologies are the main alternative. However, such a band has worse propagation than sub-1 GHz bands and a high occupancy in many environments, thus it is normally used only for certain IoT scenarios. There are 2.4 GHz technologies like Bluetooth that have proven to provide a good data transfer power consumption ratio, while others based on the IEEE 802.15.4 standard (e.g., XBee, Thread, and ANT) offer a better sensitivity [1].

Commonly, Bluetooth is used for scenarios that require short-range communications, but with the arrival of the new Bluetooth 5 standard, studies have shown that it has improved consumption and response time [2], as well as an improved range. This is achieved thanks to a new long-range mode (LE-coded PHY) that allows for adding extra sensitivity, with respect to the legacy version of the Bluetooth 4.x standard, by lowering the data rate to 125 Kbps, which makes it a rival of IEEE 802.15.4 standard technologies in terms of range; for this reason, it is compelling for indoor use considering the additional range [3]. This new feature not only improves the communications range but also makes it more stable in environments with electromagnetic interference.
