Allion Labs / Doyen Tsou
For computer workers, programming engineers, and gamers, wired keyboards have become indispensable tools. Wireless keyboards with 2.4G and Bluetooth® technology are increasing as wireless connectivity technology matures, and more and more users are choosing to use wireless keyboards to pursue speed and convenience.
Nowadays, no matter in the home, company or in the esports venue, there are wireless connection everywhere. Wi-Fi technology and Bluetooth® will use the same 2.4GHz wireless working band, so it will cause co-existence issues, not only affect the wireless connection quality, It will also cause the poor user experiences of wireless keyboard.
We have summarized the issues as below which cause by 2.4G wireless coexistence conditions of 2.4G keyboard and Bluetooth® keyboard:
- Interference caused blank words , repeat input error
- Interference caused input delay, or fail to connect with dongle.
Because these problems can lead to customer complaints, users will question the manufacturer’s quality management, and damaging branding image.
We choose three Bluetooth® keyboards form market and following the below condition to evaluate the result.
Test Environment Setup
Due to the different keyboard design, speed and frequency of keyboard press can greatly affect the test results and correctness. The robotic arm provide a uniform speed, quantitative way to perform continuous, repetitive press-pressing keyboards to ensure stability and consistency of each test result.
Also, through simulating the condition of Bluetooth® keyboards in different fields, it will be placed on RD isolation room to isolate from external signal interference and to create a clean wireless communication space for testing.
Figure 1: Bluetooth® Keyboard Wireless Coexistence Test Set Up
For simulation of interference signals, Allion can provide interference scenarios for different user scenarios, such as: home, office, shopping malls, etc., it also provides several different control methods of RF equipment simulation:
- Real Device and control the usage of power for interference simulation
- Using a test equipment (R&S. CMW100) control and transfer the Interference of the signal
Criterion of Bluetooth® Keyboards Performance
The wireless coexistence test standard provided by Allion is based on the feeling of the user experience. The items are keying correctness, Latency, and critical point analysis.
- Correctness: Press 300 times continuously by using the robotic arm, check each test poiont is the correct number of presses and no drop of word
- Latency: Using a measurement tool developed by Allion to calculate the time difference between keying the keyboard and it shows on the monitor.
- Critical point analysis: Check the keyboard critical working point under the interference condition
The following results (Table 1) are the keying correctness tested by 3 different brands of Bluetooth® keyboards. The Microsoft keyboard is the best performance in the test condition with no interference.
In the right test result with 3 interference condition (simulating a home environment with low interference), you can see that 3 brand test results are degraded compared to no interference result.
Table 1: Measured Correctness Result
| Latency | User feelings |
| Less than 100ms | Most users don’t feel |
| 100 to 200ms | Some gamers feel delay |
| 200 to 400ms | Most of user feels the delay |
| 400ms | Delay perception is obvious, users complain |
Table 2: Latency tolerance
In response to the difference in user perception (Table 2), Allion has developed an AI tool for latency measurement, based on the results obtained for latency and critical point analysis of keyboard work after interference. It is easy to assess the quality of the product and its corresponding user experience.
On this test result (Table 3) Microsoft delays in a non-interference test environment by approximately 40 to 200 milliseconds. While adding 3 interference condition (simulating a home environment with low interference), the delay is worth than no interference, but compared to the other two, which can be seen to maintain better latency and better working critical point.
Table 3 : Measured Latency and Critical Point Results
Through the above test results for keying correctness, latency, and interfered working critical point shows that Microsoft’s Bluetooth® keyboard still holds the better performance with wireless interference condition.
The problem of coexistence will become more and more obviously, Allion pay attention on this and help customer to control the product quality of wireless performance. The better user experience of your products will enhance the market competitiveness.