Allion Labs | Allen Liao
Wireless input devices for computers such as keyboards and mice are essential gadgets these days. Usually, Bluetooth® or dongles are the main ways to achieve wireless capabilities. Though the wireless standards are all capable of achieving data transmission, the usage still varies due to the different applications as well as different user needs.
For example, in business environments, it is sometimes necessary to use one mouse to control multiple computers. It is frustrating to use a Bluetooth® mouse in such a scenario, since all the computers you have previously connected to will be sending out Bluetooth® signals trying to connect your mouse. In the end, you have to turn off Bluetooth® on one computer to connect to the computer you actually want to use. To make this process a bit less irritating, the dual mode mouse was born. Using both Bluetooth® and dongle functions solves the problem of switching between devices.
Figure 1: Dual mode switches between Bluetooth® and dongle modes, making it easier to control multiple devices
Gaming is another common application for wireless devices, and gamers need extremely high standards of sensitivity and responsiveness. Most Bluetooth® devices are unfortunately unable to provide adequate transmission for gaming purposes, because Bluetooth® transfer speeds using the USB HID specification are too low to support a proper gaming experience. This is why most gaming devices use dongles to achieve gaming specs.
Figure 2: Most gaming mice use dongles to achieve gaming specs
In the article Bluetooth® Keyboard Performance Test, we discussed wireless keyboard coexistence issues, so this time we will discuss mouse coexistence performance. In offices and e-sport arenas, there is an abundance of interference in the environment. With Allion’s abundant wireless communications testing experience, we have summarized how 2.4GHz wireless coexistence issues can affect wireless mouse performance:
- Lag when moving cursor
- Complete failure to control cursor
When facing these issues, even if the mouse utilizes Bluetooth® frequency hopping or dongle frequency hopping technologies, is it enough to withstand interference? Can the end user’s business presentation or game go smoothly? These problems cause bad customer experiences, resulting in unfavorable reviews, poor sales, and negative brand image.
We will discuss wireless coexistence issues in three sections: environmental setup, performance criteria, and test results. Through this discussion, we will compare two dual mode mice and their problems under interference.
Figure 3: Dual mode mice from two different brands
Environmental Setup
All dual mode wireless mouse tests will take place in the shielding room. This prevents uncontrollable external RF interference to obtain reliable results. To analyze how interference affects the performance of dual mode mice, the testing is assisted by a fixture which moves the mouse cursor to perform consistent movements. While the fixture moves the cursor, the report rate and cursor movement were recorded. The results are instantaneous and accurate to the subsequent analysis and discussions. The setup is shown in Figure 4.
Figure 4: Dual Mode Coexistence Test Setup
Allion simulates interference from a variety of environments, in which different types of wireless interference (Wi-Fi, Bluetooth® technologies), different numbers of interference emitting devices, and different interference frequencies are taken into account. This helps engineers to understand how each variation compares to one another.
We create interference by data transmission between wireless devices such as Bluetooth® speakers, Wi-Fi routers, and smartphones, allowing us to control the frequency bands and channels to simulate different user scenarios.
Dual Mode Wireless Mouse Performance Criteria
Allion’s wireless mouse performance measurement criteria is the mouse’s reporting rate and the fluidity of the cursor movement. Our test consists of two parts—Report Rate Tracking and Cursor Movement Tracking.
Report Rate (RR) Tracking
The typical wireless mouse has a report rate of approximately 125 Hz, but when there is interfering coexistence, the report rate decreases to around 100 Hz, causing the user to experience less control and responsiveness in the mouse.
Cursor Movement Tracking
Aside from RR performance, we also record the cursor movement by video to determine the negative experiences users would potentially encounter.
Test Results
Report Rate (RR) Tracking
Figure 5 shows the effects of interference on dual mode mice from Brand D and Brand L. The x-axis shows interference conditions and the y-axis shows changes in the report rate. In general, a higher report rate is preferred.
In both Bluetooth® and Dongle mode, the report rate of the Brand L mouse drops significantly in the presence of a single Wi-Fi signal. In comparison, the Brand D mouse can still maintain a report rate of 125 Hz. When the interference condition is increased to 3 separate Wi-Fi signals, the report rate of the Brand L mouse decreases even more to a mere 40 Hz. The report rate of the Brand D mouse, however, still remains at over 100 Hz. When interference conditions are increased to 5 Wi-Fi signals and 3 Bluetooth signals, the difference between the performances of the two mice become even larger.
Figure 5: Report Rate Test Result
Cursor Movement Tracking
How do users of the Brand L mouse actually experience the interference conditions mentioned above? We will demonstrate this through Figures 6, 7, and 8. Figure 6 shows conditions with no interference: the cursor moves smoothly without any freezing or tailing. In Figure 7 with 3 Wi-Fi signals, the cursor movement becomes less smooth. In Figure 8 with 5 Wi-Fi signals and 3 Bluetooth® signals, the cursor movement becomes choppy and freezes. At this point, user experience is subpar, and users may want to return the product. Figure 9 shows the cursor performance of the Brand D mouse, where the cursor movement is less smooth than before but still in an acceptable range.
Figure 6: Cursor Performance of Brand L’s Mouse with No Interference
Figure 7: Brand L Cursor Performance with 3 Wi-Fi Signals as Interference
Figure 8: Brand L Cursor Performance with 5 Wi-Fi Signals and 3 Bluetooth® Signals as Interference
Figure 9: Brand D Cursor Performance with 5 Wi-Fi Signals and 3 Bluetooth® Signals as Interference
Conclusion
Summarizing the reporting rate and cursor performance results above, it is clear that the Brand D mouse performs better than the Brand L mouse in general and particularly in circumstances with interference. As to the reason for the striking difference in performance, we believe the following factors may contribute:
- Differences in antenna performance of each mouse
- Differences in the power output of each wireless receiver module (with consideration of battery life)
- Optimization of Dongle Mode anti-interference algorithm
The operation of peripheral products in the current 2.4GHz frequency band with interference has become the focus of vendors. An increasing amount of manufacturers are brainstorming to ensure that wireless mice can work normally through hardware, firmware, or drivers.
IoT Ecosystem Upgrade with Allion—Wireless Coexistence Validations
As more wireless products appear, wireless coexistence issues will only become more obvious to consumers. Allion understands and can safeguard your product quality. From user experience to the design of interference conditions, we can help you to strengthen your product.
For more information on wireless coexistence performance testing, please contact Allion at: service@allion.com