Unlocking Precision: How UWB and BLE Channel Sounding Are Redefining Positioning Technologies
December 2, 2024
The indoor location services market is having no trouble locating growth. Information technology research firm Gartner predicts it will become a $55 billion market by 2030. Technologies like Ultra-Wideband (UWB) and Bluetooth Low Energy (BLE) are central to this expansion, each catering to specific needs based on their unique characteristics. Thanks to its centimeter-level accuracy, low latency, and robust security features, UWB has seen widespread commercial adoption in applications requiring precise positioning like indoor RTLS, secure car access and sports tracking. Not to be outdone, BLE, meanwhile, remains essential in the Internet of Things (IoT) ecosystem due to its low power consumption, affordability, and established presence in consumer devices. For technology product developers, it’s important to understand the benefits of UWB and BLE as positioning technologies, comparing multiple factors, including accuracy, scalability, power consumption, cost, and security.
UWB has become a powerful tool for precise, real-time location measurement. It operates across a wide frequency range of 3.1 to 10.6 GHz, using Time of Flight (ToF) to calculate distances with high precision. UWB's pulse-based transmission method makes it faster and more immune to interference than narrowband signals, offering a significant advantage in complex multipath environments.
On the other hand, BLE has traditionally relied on techniques like Receive Signal Strength Indicator (RSSI), Angle of Arrival (AoA), and Angle of Departure (AoD) for positioning. BLE is evolving with the introduction of a new technique called channel sounding (CS), which significantly enhances its accuracy. BLE CS utilizes phase-based ranging (PBR) and round-trip time (RTT) to provide sub-meter positioning accuracy, although this comes at the cost of increased power consumption and longer ranging times.
The complementary nature of UWB and BLE CS is highlighted in certain applications. For example, in a warehouse, BLE CS could provide the coarse positioning estimate of an asset’s location, while UWB provides the fine positioning estimate, making them ideal partners in hybrid systems. While UWB offers superior accuracy and security, BLE’s ubiquity in IoT devices and upcoming enhancements make it a strong contender for a wide range of positioning applications.
Qorvo Senior Technical Marketing Manager Sri Sridharan shares some of his thoughts on the UWB / BLE CS landscape:
How do you see Bluetooth's competitive position compared with Ultra-Wideband?
Bluetooth has a lot of forces behind it. It has a large installed base, and other than Wi-Fi, it's the most popular technology for short-range wireless connectivity. We believe that Ultra-Wideband has a lot of merits in and of itself, especially when needing to locate items with centimeter-level accuracy. In addition, UWB has a competitive advantage in security and resilience to interference over Bluetooth as a positioning technology.
What is an example of the challenges in scaling Bluetooth CS for a wide range of devices?
Bluetooth CS as launched in version 6.0 doesn’t appear to be able to support a large scale of devices. With indoor asset tracking for example, it does not practically scale like UWB would. There are also concerns about power consumption, as Bluetooth CS uses a complex ranging procedure with long on-air times. The whole point of using Bluetooth was low power. When you start to use it for things like fine ranging, it’s not really low power anymore.
Where do you see UWB’s future applications?
We’re already seeing UWB deployed in mobile phones, cars, and industrial RTLS applications. Medical & healthcare companies are already evaluating how Ultra-Wideband can make a difference for them, as UWB can improve hospital efficiency by tracking equipment, patients, and staff. In the consumer space, UWB as a sensing technology has a lot of potential for things like detecting human presence or monitoring vital signs. Finally, if you can securely get in/out of your car with UWB, why not your home as well?
Other issues like scalability must be carefully considered with both technologies. UWB can scale efficiently in large deployments, making it suitable for environments like factories, where the precise tracking of numerous assets is crucial. BLE CS, however, faces challenges due to its complex ranging procedures, which may limit its scalability in certain applications.
Learn more here about UWB and BLE CS’s distinct advantages and adoption dependent on specific application requirements.
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