Bluetooth Low Energy Modules Bring the IoT to Life

Article By : Maurizio Di Paolo Emilio

The BGM220 Bluetooth Low Energy part is designed for a range of applications, including asset tags, beacons, portable medical and fitness...

Silicon Labs has formalized its new BGM220x module with a size of only 6×6 mm. BGM220 is an embedded solution that comes with a fully upgradeable software stack, which has been pre-certified worldwide, and firmware support to accelerate time-to-market.

The module supports Bluetooth Low Energy (BLE) 5.1, 5.2, and Mesh, and is compact with very low power consumption to optimize battery life. The new module allows device manufacturers to add security with pre-certified Bluetooth functionality to their microcontroller units (MCUs) with built-in security features, including root of trust.

Over the years, Silicon Labs has offered a variety of modules in a wide range of IoT wireless areas, including Mesh, Thread, Zigbee and Z-Wave, Bluetooth and others.  In an interview with EE Times, Matt Saunders, VP marketing and applications at Silicon Labs, said that the BG22 launched in January is currently experiencing a good market with a wide range of applications. According to the Bluetooth SIG Bluetooth 2020 market update, Bluetooth Low Energy continues to be the fastest-growing Bluetooth radio with a CAGR of 26%.

BGM220 is available in multiple packages, PCB (BGM220P) or SiP (BGM220S), and it is designed for a wide range of applications, including asset tags, beacons, portable medical, fitness, and low power Bluetooth mesh nodes. BGM220P is a slightly larger PCB variant optimized for wireless performance along with a better link budget for greater range.

Bluetooth Low Energy for IoT
Standard protocols such as Bluetooth, ZigBee, and Wi-Fi are not designed with ultra-low power, and for this reason, many OEMs have chosen to use a proprietary protocol focused on energy efficiency. The use of a proprietary protocol imposes many restrictions on the flexibility of wearable products, limiting the interoperability of the proprietary protocol itself. To address these limitations, the Special Interest Group Bluetooth (SIG) has introduced Bluetooth Low Energy (BLE) specifically designed to achieve the lowest possible power for short-range communication. BLE operates in the 2.4 GHz ISM band with a bandwidth of 1 Mbps.

The protocol is optimized to transmit small blocks of data at regular intervals, allowing the host processor to maximize the time interval in a low-power mode when no information is transmitted. The protocol is optimized to provide a few seconds of connection during data exchange. The controller implements several key tasks, such as establishing the connection and ignoring duplicate packets, allowing the host processor to continue to remain in low power mode.

The combination of ultra-low-power wireless communications, small size, and low duty cycle sensing applications allow the development and installation of maintenance-free IoT sensor nodes. The changes included in Bluetooth LE significantly reduce the power supply current from classic Bluetooth milliamps to a few microamps in BLE. Bluetooth Smart IoT nodes can operate for months and even years with a small button cell without the need to change or recharge it.

“The most important parameter varies by application. But there are a few common areas that I think are relevant in the majority of applications. For example power consumption or battery lifetime. With the introduction of Bluetooth mesh, and its use in lighting, there are a lot more line power devices, but there’s still a huge number of battery-powered applications in Bluetooth where a longer lifetime adds real value to the user. So the consideration for power consumption is not just in terms of how much energy the device uses to manage the computation and communications stack, but also if the RF design has been developed with low power operation in mind.

A more efficient RF technology and design is going to give more battery lifetime. Another area I believe is important is the physical size of the solutions; a lot of Bluetooth applications are very compact. Having a small physical implementation on the chip obviously helps in a space-constrained design, but again, related to the RF parameters, being able to build a solution that is more compact such as you can with the BGM220S, that delivers some real advantages to the developer as well. And then I also think of security. This is something that is becoming a very important parameter, not just in Bluetooth, but in many other IoT technologies,” said Saunders.

The Bluetooth standard, even in its recent evolution as Bluetooth Low Energy (BLE), continues to find its place on a large number of devices. Among the many standards of communication used for connecting two devices, in fact, Bluetooth has gained its importance due to its simplicity of use and the possibilities it provides to connect practically everything with everything. There is an increasing number of applications that use IoT sensors characterized by a reduced duty cycle that provide intermittent communications: in this way, it is possible to ensure the operation process using the energy stored from renewable sources.

Figure 1: BGM220P block diagram. It combines an energy-friendly MCU with a highly integrated radio transceiver in a PCB module
Figure 1: BGM220P block diagram. It combines an energy-friendly MCU with a highly integrated radio transceiver in a PCB module. Click the image to enlarge.

The continuous growth in the number of IoT devices and applications in various vertical sectors of commerce and industry has increased the need for new and stronger cybersecurity measures to defend security and privacy. The growing demand for cybersecurity measures and regulations in the Internet of Things (IoT) ecosystem, which affects businesses and consumers, aims to achieve better levels of protection against malware and external threats.

The “Stride” classification model, originally developed by Microsoft, lists the potential security threats that an IoT device or the users of that device might face: spoofing, tampering, repudiation, information disclosure, Denial of Service (DoS) attacks, and EoP of possible malware within an infected system.

Bluetooth Module
SoCs (Systems on Chip) are ideal for IoT device manufacturers who need maximum flexibility in developing their IoT devices, with highly customizable software and RF design options. SiP modules, on the other hand, are ideal for device manufacturers who need the smallest pre-certified Bluetooth Low Energy form factor with little or no RF design or design, while PCB modules offer many of the advantages of SiP modules, but at a lower cost.

Challenges require product developers to keep pace with strong security standards in a product of the Internet of Things. The security of these IoT products is rapidly becoming mandatory in various countries around the world.

Internet of Things security is a critical aspect to consider in order to protect corporate brands, end-user privacy, and the commercial viability of products. Vulnerabilities can be exploited both through remote attacks on the Internet and through practical physical attacks.

“Developers using Silicon Labs’ wireless product portfolio, including those in the BGM220 portfolio of modules, have access to a number of technologies designed to protect their product, including Secure Debug, Secure Boot with Root of Trust & Secure Boot Loader,” said Saunders.

He added, “We’re working with customer security communities, third-party security experts to provide cutting-edge security solutions on our products that help protect IoT devices connected today, but also with a certain level of upgradeability to help them continue to protect tomorrow, to maintain product evolution. We’re infusing our high-performance Bluetooth products with a suite of state-of-the-art security features we’ve called Secure Vault,” said Saunders.

The security functionality Silicon Labs offers is its Secure Vault: a suite of hardware and software security protections for IoT devices to protect their brand, product design and consumer data.

Based on the EFR32BG22 SoC, the BGM220P/S enables Bluetooth Low Energy connectivity for future-proof capability for feature and OTA firmware updates, enhanced security features, and low energy consumption. EFR32BG22 SoC features a 32-bit ARM Cortex M33 core, a 2.4 GHz high-performance radio, 512 kB of flash memory, a rich set of MCU peripherals, and various clock management and serial interfacing options.

BGM220P modules are a full solution that comes with world-wide regulatory certifications, advanced development and debugging tools, and support that will minimize and simplify the engineering and development process of your end-products helping to accelerate their time-to-market.

BGM220 has Hardware Cryptographic Acceleration for AES128/256, SHA-1, SHA-2 (up to 256-bit), ECC (up to 256-bit), ECDSA, and ECDH. True Random Number Generator (TRNG) compliant with NIST SP800-90 and AIS-31 and Secure Debug with lock/unlock.

Thanks to the presence on board of software stacks, the devices require the commitment of modest resources from the processor, thus giving the possibility to add wireless connectivity to any microcontroller (MCU).

BGM220S and BGM220P support Bluetooth Direction Finding, all while delivering up to ten-year battery life from a single coin cell. The ability to find the direction is still relatively new. “Silicon Labs is working directly with some companies to provide a very accurate direction finding for tracking and moving indoor assets,” said Saunders.

The combination of Bluetooth and Wireless also creates problems in terms of RF performance of IoT devices in an environment dominated by the radio emissions of a system or Wi-Fi configuration. A managed coexistence solution is very useful.

Figure 2: BGM220S block diagram. It combines an energy-friendly MCU with a highly integrated radio transceiver in a SiP module with a robust, integrated antenna.
Figure 2: BGM220S block diagram. It combines an energy-friendly MCU with a highly integrated radio transceiver in a SiP module with a robust, integrated antenna. Click the image to enlarge.

The problems you get from coexistence manifest differently depending on where you are in the system. In an end node, poorly managed systems can cause lost packets which leads to reduced battery life because the radio is continually trying to resend. In the gateway, it manifests itself so that the radio, the most powerful of radios, will cancel low-power radio transmission channels, needing a managed solution. “Having this managed coexistence allows you to get the best profile and performance from all the radios in your system,” said Saunders.

Connectivity is a fundamental pillar of any IoT system. Easy-to-manage solutions provide the energy-saving features and security resources required to protect an IoT device for project implementation. The Bluetooth Low Energy has evolved to become the key element of connectivity thanks to its profile flexibility and shallow power features. BLE is replacing proprietary protocols to become the de facto standard of connectivity in ultra-low power IoT devices.

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