A deep dive into Bluetooth technology, standardisation and applications

• intro on Bluetooth SIG, the creation, its structure and operation
• the architecture of Bluetooth low energy (4.0), link layer and application aspects
• enhancements added to BLE (a selection of the key additional features)
• upcoming features in emerging standards

Wireless audio streaming is omnipresent. Due to the ubiquity of Bluetooth (BT) chips in audio-capable devices sold today, the wireless audio streaming solutions provided by the Bluetooth Special Interest Group are widely used to realize such use cases. The most recent addition to its standards portfolio is Bluetooth Low Energy (LE) Audio. LE Audio focuses more on power efficiency than the classic version of Bluetooth. It also introduces new wireless audio streaming features and seeks to provide better audio quality than standard Bluetooth.

This presentation introduces the design of Bluetooth Low Energy (BLE) technology for two challenging applications. Firstly, we present a low-power, wirelessly synchronized multi-IMU platform developed to aid in physiotherapy treatment, enabling remote monitoring of exercises. This wireless functionality not only enhances patient comfort during movements but also ensures ease of use. In the second application we track the continuous movement of plant leaves. Tracking plant movements presents a unique way of assessing their physiological condition and detects stress. We introduce a tailored design featuring a lightweight wireless sensor system utilizing both LoRa and BLE communication, simplifying the collection of this movement data.

We present 2 different methodologies that can be used for the calculation of relative angles and locations between transmitters and receivers.

We first give a quick introduction into BLE direction finding, its strengths and weaknesses and some tips on how it can be implemented.

After RF-based localization techniques, we present a localization method using acoustic signals. This technique will be described by showcasing an industrially relevant problem: the automatic extraction of a synoptic view for conference rooms.

We present investigations on the use of the LC3plus codec for practical, distributed audio processing. Three specific applications will be considered: (1) post-processing the received signal to remove artefacts due to lossy coding, (2) source localisation using the lossily encoded signals from distributed arrays, and (3) blind source extraction in ad hoc array scenarios, where both source and microphone positions are unknown. We demonstrate solutions for each of these cases by leveraging a combination of deep learning and statistical signal processing. For coded signal recovery, this results in significant quality improvement. For source localisation, surprisingly, including the codec in the training of the localisation network yields results that are better than using the unencoded signals. Lastly, applied to ad hoc arrays, we present a novel, general, framework based on clustering microphones around individual sources. The clustering approaches are robust to codec-induced signal distortions — thus opening opportunities for exploiting the full potential for ad hoc wireless acoustic networks.

• Demo 1 – KU Leuven: a BLE-connected plant-sensor and a multi-sensor solution for supporting physio-therapeutic treatment
• Demo 2 – IoSA: the internet-of-small-animals – Bluetooth-enabled animal behavior monitoring
• Demo 3 – Cochlear and imec-IDLab-UGent: audio streaming with Broadcast Isochronous Group (BIG)
• Demo 4 – Televic Conference: a language distribution system with LE audio
• Demo 5 – imec-IDLab-UGent: Bluetooth localisation for speech enhancement
• Demo 6 – NXP Semiconductors: multi-channel sound over BLE
• Demo 7 – imec-NL @ Holst Centre: high-accuracy distance measurement / channel sounding with Bluetooth

Bluetooth Low Energy (BLE) technology has emerged as a versatile protocol for addressing diverse challenges in modern society. In this presentation, we delve into two compelling use cases that exemplify the potential of BLE applications.
Firstly, we explore the efforts of IoSA (Internet of Small Animals), a spin-off company of the University of Antwerp and imec, leveraging BLE technology to track and monitor small animals.
Secondly, we delve into ongoing research focused on enhancing train travel experiences through BLE-based localization. This research not only promises to increase the efficiency in public transportation, but also opens up avenues for higher revenue.

Wireless Bluetooth audio communication has become an inherent part of everyday life, from listening to a podcast on our headphones to streaming music on multiple speakers. The concept of broadcasting audio using Bluetooth has been standardized as Auracast. It enables a variety of use cases, both for personal use as well as in public venues: flight-specific broadcast information in an airport, assistive listening systems in an auditorium or theater, music streaming to an infinite number of speakers, etc. To cope with the unpredictability of wireless media, several configurable parameters are provided to an Auracast system, to optimize the listening experience of an audio receiver that is subjected to volatile environmental conditions. Cochlear and imec-IDLab-UGent have collaborated to set up a benchmarking platform that is able to provide insights into the listening experience at an audio receiver, both via a simulation model as well as a testbed containing Bluetooth-capable hardware. The results from the model are shown to mimic the observed behavior in the testbed and valuable insights can be gained regarding the impact of a specific configuration of the Auracast system on the listening experience, under varying wireless link conditions.

We discuss latency with Bluetooth® LE Audio as last hop in a wireless language distribution system.

• batteryless BLE nodes with energy buffering
  
• analysis of duty-cycling for the BLE nodes to maintain its operation
• scalability aspects of BLE mesh networking
• method for QoS in BLE mesh networks