Visualizing Bluetooth and Wi-Fi coexistence issues on the IoT
June 14, 2018
To minimize the impact of RF interference in the 2.4 GHz spectrum, protocol and spectrum analyzers have become an increasingly important apparatus in the developer?s toolbox.
Bluetooth devices are everywhere around us, and more are on the way. Starting with Bluetooth Classic-based wireless office accessories in the 90s, Bluetooth has expanded its reach into smartphones (Bluetooth Low Energy/4.0), home appliances and retail beacons (Bluetooth 4.2), and now into mesh networks for building monitoring and control, security, and a host of other applications (Bluetooth 5).
The challenge here for embedded and Internet of Things (IoT) developers is that three leading wireless local area network technologies – Bluetooth, Wi-Fi, and 802.15.4 standards such as Zigbee and Z-Wave – all rely heavily on 2.4 GHz spectrum. All of these wireless signals operating in the same frequency band can result in heavy RF interference, with consequences ranging from increased error rates to a total loss of data.
Meanwhile, there is a growing desire to add multi-protocol wireless capabilities to connected devices. For example, with Bluetooth and Wi-Fi integrated into the same system (or perhaps on the same piece of silicon), devices could use low-power, low-data rate Bluetooth connectivity to exchange information with nearby devices and Wi-Fi for higher bandwidth Internet communications. This, of course, exacerbates the RF interference problem.
To minimize the impact of RF interference in the 2.4 GHz spectrum, protocol and spectrum analyzers have become an increasingly important apparatus in the developer’s toolbox. One such analyzer that addresses the issues of multi-protocol wireless spectrum interference is the Bluetooth Vanguard All-In-One Protocol Analysis System from Ellisys.
[Figure 1. The Bluetooth Vanguard All-In-One Protocol Analysis System supports Bluetooth Basic Rate (BR), Bluetooth Enhanced Data Rate (EDR), BLE, Wi-Fi, 802.15.4, spectrum, and a local I/O.]
Visualizing IoT coexistence with all-in-one analysis
The Bluetooth Vanguard protocol analyzer supports concurrent wideband analysis across all 16 channels of the 2.4 GHz spectrum, capturing packets for wireless protocols that include Bluetooth Classic, BLE, Bluetooth Mesh, 3 x 3 Wi-FI 802.11a/b/g/n/ac, 802.15.4, and raw 2.4 GHz spectrum energy. The development system also enables testing of physical I/O interfaces such as HCI, UART, SPI, I2C, SWD, Audio I2S, and WCI-2.
To ensure the highest level of accuracy in coexistence testing, Bluetooth Vanguard integrates a hardware-accelerated protocol engine that helps guarantee throughput and minimize latency so that multiple wireless data streams can be characterized simultaneously without loss. When used in conjunction with Ellisys’ software suite, wireless engineers can visualize complex protocol and RF behavior with nanosecond resolution (Figure 2).
[Figure 2. When paired with Ellisys’ analysis software, the Bluetooth Vanguard All-In-One Protocol Analysis System enables nanosecond resolution for debugging complex protocol and RF behaviors.]
SuperSpeed USB 3.1, Gigabit Ethernet, and Power over Ethernet/USB Power Delivery allow the Bluetooth Vanguard system to be controlled by local PC or remotely, which is particularly useful in lab settings or when measuring RF and protocol performance in hard-to-access areas with high levels of interference.
Vanguard’s remote management capability also pairs with a reconfigurable, field-upgradable digital radio and capture engine, which allow the system to support new and emerging features over time. For instance, as the Bluetooth Special Interest Group (SIG) added features like AES security, connectionless broadcast, Coded PHYs, and 2 Mbps bandwidth for BLE, the Vanguard platform and other Ellisys analysis tools were able to seamlessly add support well before the specifications were released.
This not only helps protect the system itself from obsolescence, but also provides development teams with additional lead time as new technologies are introduced to the market.
A reconfigurable toolbox
The landscape of IoT protocols and wireless spectrum is a congested one, and that will continue to be the case given the number and scope of devices being connected. Engineers designing high-quality wireless products in this fast-moving environment need to equip a reconfigurable toolbox. Versatile multi-protocol spectrum analyzers are perhaps the best place to start.