Key WLAN Signal Evaluation Tests at Product Design and Development
Evaluation Process at WLAN Product Design
Many different types of products are connecting to the Internet as a result of the recent spread of IoT. These Internet connections are implemented by assembling products using WLAN modules that conform to the IEEE 802.11 standards. However, when using existing products and new products under development for IoT applications, not only must the chosen WLAN module be evaluated standalone, but it is also best to evaluate the final assembled product.
The following table lists the product development processes and examples of tests for signal quality at each stage.
Table 1: Product Development Process and Required Tests for signal quality
Ensuring product quality requires various processes and evaluation tests as shown in the above table. However, cutting the total development time by omitting some of these tests without thinking deeply runs the following risks.
- WLAN communications problems occur even after prototyping and final product development.
- Customer may claims about inability to communicate occur after product release despite confirming operation in the test laboratory.
During the development process, it is best to focus on the points for choosing the WLAN module and selecting the WLAN evaluation method so as to ensure effective and appropriate testing using a WLAN tester at each phase. Following this procedure not only prevents the need for redesign and cuts development time actually but also improves product quality, customer satisfaction, and brand image.
>>> Continue to Key Points at WLAN Product Design
Column: What is IEEE 802.11?
WLAN is a wireless communications technology standardized by IEEE 802.11 defined by the Institute of Electrical and Electronics Engineers (IEEE). IEEE 802.11 describes RF standards and related test methods.
To ensure the quality of WLAN communications, basic measurement items and criteria related to transmission and reception tests are described in the standard; when a WLAN product meets these criteria, it is evaluated as having the required RF performance.
Column: Is the product OK if it can connect to an Access Point?
The answer is no.
Even if a high IP throughput is measured when connected to a commercial Access Point, this does not confirm that there are no problems with signal quality (RF performance). IP throughput is not dependent only on RF performance but also changes greatly depending on the performance of the higher-layer protocol stack and the amount and type of sent and received data. Moreover, since the modulation method also changes according to the data rate, RF performance also changes accordingly.
Consequently, even when the RF performance has serious problems, they might be overlooked because the IP throughput result was unaffected at some measurement condition by chance. Or the throughput might have dropped under different conditions.
Furthermore, at wireless communications with a commercial Access point, there is no control of the data rate being used. When propagation conditions are ideal, generally, only the best signal rate supported by the Access Point and module is used. As a result, when there is a transmit/receive problem at a specific data rate, discovering it is hard when using a commercial Access Point.
At first use of a module in various environments after product shipment, it may become apparent that the throughput is much lower than other modules. Avoiding this type of problem requires evaluation using a measuring instrument that can quantitatively capture the RF performance at each data rate.
Key Points at WLAN Product Design
The following guides are available for download and introduce key points at product design to prevent the above-described problems.
WLAN Product Design Guide
- Parts selection DOWNLOAD NOW
This guide explains which WLAN module performance and specifications should be the focus of attention as well as the best way to select modules to include in products. Read this guide to understand the basics of module comparison testing.
- Product design, development and Evaluation DOWNLOAD NOW
At the first step, product design and development require selecting the wireless standard based on the usage environment for the product with the built-in WLAN module. This guide explains key points for implementing a WLAN communications device.
Testing RF performance after final assembly is important because the RF performance of final products is different from the RF performance (WLAN signal quality) of standalone WLAN modules. In addition, it is also important to test the final signal quality including antenna performance.
- Certification testing DOWNLOAD NOW
Testing at certification test sites is time-consuming and expensive. Pre-certification test in the laboratory can help to perform certification test smoothly.
There are two key parts to certification testing: compliance with technical standards, and interconnectivity confirmation tests. This guide explains the contents of these tests.
Failing a certification test for some reason incurs heavy work burdens to repeat tests as well as high do-over costs.
Consequently, in-company pre-testing using the same test contents to confirm compliance and performance help assure a successful and smooth regulatory certification test,
There are two types of test: 1. The regulatory certification test, and 2. The interconnectivity certification test.
- After Commercial Release DOWNLOAD NOW
After the development process has been completed and the products are ready for the market, RF performance evaluation is still required in order to maintain high customer satisfaction.
In this downloadable document, we introduce RF measurements necessary for mass production of homogeneous products, confirmation of changes in RF performance before and after changes in onboard software, and various RF performance evaluation methods for quality improvement.
Other WLAN Product Design Guides
Column: Example of WLAN Module Evaluation
The following items are required when evaluating WLAN modules using the WLAN tester.
The module can be connected using the following three steps when the WLAN is operating in
the network mode.
- Select AP (Access Point Mode) as the WLAN test mode.
- At the WLAN tester, set the DUT Standard Output Power and the Rx power expected to be received by the WLAN tester.
- Measure at the DUT WLAN Rx settings by connecting the DUT to the WLAN tester by choosing the WLAN tester name as the Access Point.
Key Features of Wireless Connectivity Test Set MT8862A
- Network Mode Applications: Uses standard WLAN protocol messaging (WLAN signaling) to measure by establishing wireless link with WLAN product
- Supports IEEE 802.11a/b/g/n/ac/ax
- 2x2MIMO Rx sensitivity and Tx power measurement functions
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