Ed. 08 | UWB vs. Bluetooth: Choosing the Right Technology for You

Humans have sought to transmit informationsince the dawn of civilization. Language, the most basic tool, evolved alongside "knotting," a method for recording information and overcoming the limitations of time and space. Ancient chiefs and wizards established rules for knotting, using rope thickness, knotting styles, size, and spacing to convey different messages.

Beacon towers, which arose in the Shang and Zhou dynasties, solved the problem of long-distance, rapid information transmission. This method fulfilled the need for swift communication over vast distances.

The late 19th century saw the birth of modern information and communication technology, echoing the ancient pursuit across time and space.

Wireless communication technology, emerging in the 20th century, allowed humans to transmit voice and data without wires. Today, it is a cornerstone of communication. Numerous wireless transmission technologies have emerged, including Bluetooth, UWB, WiFi, PCS, GPS, NFC, and more.

Meeting a Rival: Bluetooth vs. UWB

The short-range wireless communication landscape is populated by various players. In recent years, terminal products incorporating Bluetooth, UWB, and NFC have emerged in location services. This article delves into the differences between Bluetooth and UWB technologies in the context of positioning services.

Bluetooth technology, a low-power, low-cost short-range wireless communication standard, operates on a global universal frequency band for data transmission, bridging the gap between incompatible mobile devices. Essentially, it leverages low-power radio waves (2.4-2.485GHz) to exchange data between devices within a 10-meter radius.

Initially, Bluetooth devices were predominantly used for audio applications. The Ericsson T39mc, the first mobile phone featuring built-in Bluetooth, ushered in the era of Bluetooth headsets. Over two decades of development have seen Bluetooth undergo numerous updates and iterations, from Bluetooth 1.0 to 5.4. From classic Bluetooth (BT) to low-power Bluetooth (BLE), significant advancements have been made in data transmission rate and distance, expanding the range from the initial 10 meters to 300 meters.

Since the introduction of Bluetooth 4.0 in 2010, BLE has garnered attention. Unlike classic Bluetooth, suitable for prolonged audio transmission, BLE excels in pairing, power consumption, positioning, and security. Three connection types are available: single-mode, dual-mode, and both classic Bluetooth and low-power Bluetooth. According to the Bluetooth Technology Alliance, single classic Bluetooth mode faces future growth limitations, while single low-power Bluetooth mode will dominate.

Beyond audio, Bluetooth technology has found success in location services, data transmission, and device networking. Driven by market demand for positioning technology, Bluetooth 4.0 integrated positioning service capabilities through the RSSI positioning principle. Bluetooth positioning has evolved from RSSI-based mechanisms to indoor positioning in conjunction with Wi-Fi and further to AoA and AoD methods, achieving centimeter-level positioning services.

RSSI positioning leverages the relationship between RSSI signal attenuation and distance to calculate terminal position. Its accuracy typically ranges from 3-5 meters, with a latency of approximately 3 seconds. Environmental factors significantly impact signal strength, limiting its maximum transmission distance to 10 meters. Bluetooth 5.0, integrating Wi-Fi technology, enhances indoor positioning capabilities, achieving sub-meter accuracy. Unlike RSSI, AoA and AoD utilize phase differences in the antenna array to convert directional information for positioning.

With the evolution of Bluetooth technology and the emergence of numerous Bluetooth products, it has become an integral part of the Internet of Things. Its continuous advancements in device power consumption, data transmission, location services, and device networks have led to applications in various sectors, including medical health, retail, warehousing and logistics, and smart lighting.

In the medical health sector, Bluetooth is at the heart of smart wearable devices. Smart bracelets, necklaces, and other devices rely on Bluetooth for wireless communication and data exchange, maximizing the standby and running time of these devices through its low power consumption.

Bluetooth technology boasts a mature ecosystem and widespread adoption in positioning applications. Compared to UWB, it holds significant competitive advantages in low cost, low power consumption, and a robust ecosystem. Nearly all mobile terminals are equipped with Bluetooth chips and modules, with Bluetooth gateways and base stations serving as intermediary devices.

Ultra-wideband (UWB) technology, originating in the 1960s, operates in a spectrum ranging from 3.1 to 10.6 GHz. Unlike other wireless data transmission methods, it employs carrier-free communication based on non-sinusoidal narrow pulse data transmission. UWB signals exhibit high security and are resistant to interference from other signals.

Initially, UWB technology was solely used for military positioning purposes. In 2002, its applications extended to civilian wireless communications. Through three positioning modes: ToF (time of arrival), TDoA (time difference of arrival), and AoA/DoA (angle of departure and angle of arrival), UWB achieves a positioning accuracy of 10 cm, with a coverage range of 10-200 meters and low latency.

UWB technology shines in networked asset tracking, leveraging its centimeter-level precise ranging capabilities and security. Apple's AirTag, released in 2021, utilizes UWB to enhance the "Find" function in the Apple ecosystem, enabling precise object location through UWB-based sensing of connections between mobile phones and objects.

UWB technology finds widespread use in personnel positioning management within challenging environments, such as hospitals, factories, and underground mine tunnels. In medical settings, the UWB positioning system tracks the location of medical staff and patients, improving medical assistance response times. In factories, mobile assets, including materials and equipment, are positioned and managed. For underground mine workers, UWB positioning technology ensures safety while working.

The automotive industry is witnessing the adoption of keyless technology, with UWB playing a significant role. Platforms like BMW, Mercedes-Benz, Weilai, and BYD are actively researching and developing UWB digital keys. BMW has already incorporated UWB for keyless entry in newer models like the iX, and UWB digital keys are poised for widespread adoption in the automotive industry.

UWB technology has undergone over a decade of development but remains unstandardized. As UWB transitions to large-scale commercial deployment, the FiRa (Fine Ranging) Alliance was established in August 2019 to foster an interoperable, universal, and interconnected UWB ecosystem.

The primary allure of UWB lies in its exceptional positioning and direction accuracy, enabling precise object location with an error margin of just a few centimeters, achieving centimeter-level accuracy. This surpasses the positioning accuracy of Bluetooth technology. While UWB boasts high-precision positioning capabilities, low-power Bluetooth (BLE) maintains a significant advantage in Bluetooth technology by achieving low power consumption in both standby and connected states.

Each relies on its own ability

Bluetooth and UWB are two popular short-range communication technologies, each with unique strengths. They are constantly competing while expanding their applications.

The FiRa Alliance's latest FiRa 2.0 release focuses on the physical (PHY) and media access control (MAC) layers. It supports downlink time difference of arrival (DL-TDoA) ranging specifications, dynamically scrambled data frames, and improved angle of arrival (AoA) measurement accuracy through one-way ranging (OWR), competitive ranging, and physical layer security configuration. These advancements expand UWB's reach into consumer and industrial markets, enabling applications like centimeter-level accurate indoor navigation, asset tracking in factories, and smart remote control. However, the increased array antenna layout remains a challenge.

The growing demand for high-precision positioning services has led to widespread adoption of Bluetooth technology in diverse scenarios such as medical health, retail, warehousing, and logistics. Bluetooth is expected to improve in latency, data transmission, and high-precision positioning.

While positioning is a secondary function in Bluetooth, a new high-precision mode called Bluetooth channel detection (CS) has emerged. This technology analyzes phase changes of radio frequency signals across different frequencies to improve ranging accuracy. It doesn't require array antennas, enabling safe, high-precision ranging with a single antenna. The Bluetooth Technology Alliance plans to launch Bluetooth channel detection technology in the second half of the year.

Conclusion

These two wireless communication technologies offer various options for market demand, considering factors like transmission distance, rate, power consumption, cost, stability, and security.

Choosing between them is not a simple decision. As UWB and Bluetooth technologies advance and expand their applications, their integration is becoming more common. This combined approach will become mainstream and continue to play a significant role in wireless communications.

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