Analysis and Tools for Improved Management of Connectionless and Connection-Oriented BLE Devices Coexistence

Abstract

With the introduction of low-power wireless technologies, like Bluetooth Low Energy (BLE), new applications are approaching the home automation, healthcare, fitness, automotive and consumer electronics markets. BLE devices are designed to maximize the battery life, i.e., to run for long time on a single coin-cell battery. In typical application scenarios of home automation and Ambient Assisted Living (AAL), the sensors that monitor relatively unpredictable and rare events should coexist with other sensors that continuously communicate health or environmental parameter measurements. The former usually work in connectionless mode, acting as advertisers, while the latter need a persistent connection, acting as slave nodes. The coexistence of connectionless and connection-oriented networks, that share the same central node, can be required to reduce the number of handling devices, thus keeping the network complexity low and limiting the packet’s traffic congestion. In this paper, the medium access management, operated by the central node, has been modeled, focusing on the scheduling procedure in both connectionless and connection-oriented communication. The models have been merged to provide a tool supporting the configuration design of BLE devices, during the network design phase that precedes the real implementation. The results highlight the suitability of the proposed tool: the ability to set the device parameters to allow us to keep a practical discovery latency for event-driven sensors and avoid undesired overlaps between scheduled scanning and connection phases due to bad management performed by the central node.

Efficient Communication Scheme for Bluetooth Low Energy in Large Scale Applications

“…A number of papers focus on collisions in the communication channel, energy efficiency and node discovery delay, i.e., time from the first advertisement transmitted to the first time the scanner correctly receives one advertisement (but not necessarily the first one) and notices the presence of a node. This includes analyses of different versions of the BLE standard [15,21], operation patterns including connection-less and connection-based modes [5,6,[22][23][24][25], passive and active scanning [15,16], and various choice of communication parameters (e.g., advertisement/scan/connection interval, scan window) [6][7][8]15,21,23].…”

“…BLE nodes can simultaneously work in connection-based and connectionless mode. Therefore, some papers address such scenarios, e.g., the article by Del Campo et al [6] analyses the system dedicated for assisted ageing living (AAL) scenario where some of the sensors are continuously connected and some are sending their measurements only form time to time, using advertisement messages. They have proposed a tool to support selection of BLE device parameters in the system to ensure practical discovery latency and avoid overlaps between scanning and connection phases.…”

“…So far, many authors (e.g., [6][7][8][9][10]) focused on passive scanning and determining optimal settings for the nodes and scanners (namely advertisement interval, scan window, and scan interval) when a large number of nodes is deployed in small area. They have analysed the impact on the energy consumption, effective data throughput, and detection delay (the time until the scanner correctly receives the first data packet from a node), and proposed methods to choose settings for different scenarios.…”

Experimental Evaluation of Advertisement-Based Bluetooth Low Energy Communication

“…Furthermore, there are some aspects that suggest that connectionless BLE, when compared to WiFi, ZigBee/IEEE 802.15.4, and even sub-GHz solutions, can be better suited for small-to-medium network size IoT applications. Firstly, it does not have the scaling issue, which means that theoretically it can effectively communicate data between thousands of devices, and is often proposed as a method for opportunistic data transmission [13,14], monitoring applications [15], and localization systems based on radio signal strength [3,16]. BLE outperforms other 2.4 GHz technologies in terms of energy costs, throughput, and latency [7,17].…”