Dense Deployment of BLE-Based Body Area Networks: A Coexistence Study

The issues of cross-technology interference and coexistence in the unlicensed 2.4-GHz spectrum band among various technologies including WiFi, ZigBee, and classic Bluetooth have been studied extensively. However, it remains relatively understudied for Bluetooth low energy (BLE), especially in densely deployed scenarios. In this paper, we develop a testbed to conduct our experimental studies, focusing on BLE and its coexistence capabilities when being deployed in a dense environment, under possible interference from WiFi and ZigBee/IEEE 802.15.4. One scenario of interest is a network of several co-located BLE-based BANs, each of which is designed in a star topology with one gateway and multiple BLE sensor nodes. The second scenario represents a highly heterogeneous network where each BAN now carries both BLE and ZigBee sensors, while being exposed to interference from external WiFi transmission. Experiments are carried out on our testbed, which are built based on low-cost, light-weight off-the-shelf components and state-of-the-art BAN protocols. Our results show that the performance of BLE is relatively robust to interference from other BLE transmissions as well as those from nearby ZigBee and WiFi devices. In addition, the deployment of the testbed on human bodies results in no performance degradation for the network.

I. Introduction

Widespread development of the Internet-of-Things (IoT) and low-power wireless technologies has led to profound interest in wireless body area networks (BANs). A BAN is composed of multiple nodes of very low-power, short-range sensors, sending and receiving data through wireless technologies. The sensors collect data from their surrounding environments, such as temperature, pressure, humidity or physiological conditions from a human body. Primary applications of BANs are in the healthcare domain, e.g., for ubiquitous monitoring of patients with chronic disease such as heart attack; but other use cases include military and sports.