The importance of wifi testing for smartphones

Today, smartphones are indispensable in our lives, and the performance of different brands of mobile phones is uneven. This paper analyzes the common indicators such as signal strength, speed and delay and causes of the problems. Learn more about wifi, better buy wifi signal jammer device, protect our wifi security, protect our mobile phone, and finally protect our information security.

In recent years, with the strong rise of domestic mobile phone brands in the domestic and international market, the competition in the smartphone field has entered into a white heat. However, due to the maturity of chip and hardware technology, the mobile phone functions are becoming more and more similar, and the performance parameters are becoming more and more similar, and the differentiation between mobile phone brands is becoming more and more difficult. At the same time, new features and running parameters can easily cause aesthetic fatigue to consumers. As a result, consumers increasingly value mobile phone user experience, stability and durability. Therefore, the ability to continuously provide the best user experience and trustworthy quality is the key to the success of the mobile phone brand in the future.

Provide network connection on the mobile phone has two technologies, a born with mobile cellular mobile networks, the second is in late but rapid development of IEEE802.11 wireless local area network (LAN), more familiar with WiFi this name. 802.11 technical work in non-authorized frequency segments, with low cost, high speed, simple deployment and wide coverage. In homes, shopping malls, hotels, businesses, public facilities and so on, the Internet is the preferred way for users to access the Internet. According to operator statistics, mobile phones are much more mobile than mobile phones, both in terms of data and time spent on mobile phones.

Because the WiFi component carries the most data traffic and usage time of the smartphone users, the performance and quality of the WiFi components greatly influence the user experience. Today, however, due to the lack of attention of some mobile phone brands on the quality of WiFi components, the user experience of mobile phones has decreased and the brand recognition has been reduced. Among them, the WiFi signal is weak, the Internet is slow, the delay of several big problems is affected by more users complaints, the image of these phone brands has a negative impact. Therefore, how to improve the quality of mobile WiFi has become a problem that manufacturers need to pay attention to.

By checking the WiFi icon at the top of your phone's screen, users can get a direct view of the current strength of the WiFi signal. Sometimes two different brands of mobile phones are clearly in the same location, displaying a different number of signals, so the user will complain about the poor WiFi signal of the cell phone with few signals. This is related to the performance of the mobile WiFi receiver. In connection with the router, the radio frequency receiver periodically measures the broadcast packets sent by AP, and calculates the RSSI value (indicating signal strength of the receiving signal). Based on the size of RSSI, the signal strength is displayed on the operating system. In normal circumstances, the closer the phone is to the router, the higher the RSSI value is, indicating the stronger WiFi signal received. The farther away the phone is from the router, the lower the RSSI is, indicating the weaker the WiFi signal.

Sometimes the user can see the WiFi signal on the cell phone, but the actual speed of the Internet is very slow, and even the user experience is seriously affected. The cell phone shows that there is no problem with the signal, so what's the problem? The problem is the transmitter power of the cell phone. The transmitter power is very important for mobile phones - high launch power, which can power the phone too quickly and require frequent charging. The low power transmission will make the uplink signal fail to reach the receiving antenna of the router after the path attenuation, thus reducing the actual working scope of the mobile phone. Therefore, we need to conduct strict calibration and testing of WiFi emission power in the process of mobile phone manufacturing to ensure the accuracy of transmission power.

Because of the wireless communication is a two-way street, through in the process of manufacture for mobile WiFi transmitted power and receiver sensitivity to strict calibration and test, we can ensure that the mobile phone of uplink and downlink link in the maximum working range matching, and there will not be one of them dragging.

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Because WiFi is mainly working in unauthorized frequency bands, the spectrum is more crowded, so experienced users will often choose to switch the router to the smaller frequency. But when the user's phone is connected to a router with different frequency points, the signal strength and Internet speed can sometimes be found to be significantly lower. That's because WiFi works in two main frequencies, 2.4GHz and 5GHz. Each frequency segment is divided into multiple frequency points. For example, the 2.4GHz band has 14 available frequencies from 2412MHz to 2484MHz, while the 5GHz band is more bandwidth wide and has 24 frequency points in the range of 5180MHz to 5825MHz. For mobile WiFi components, the rf performance of different frequency bands is very different. So in production test process, should be of the two frequencies of multiple frequency points in turn for calibration and testing, to ensure that mobile phone after they leave all at 2.4 GHz and 5 GHz frequency point can work normally.

As a wireless LAN technology, WiFi is smaller than cellular mobile communication, and the terminal location is unchanged or only has low speed movement. Therefore, the frequency selectivity and spatial orthogonality of WiFi signals are better than that of the widely covered cellular networks. Therefore, WiFi can better utilize the advantages of high bandwidth and multi-antenna technology to achieve a large rate increase.

Some new popular Internet applications such as online games, due to their real-time and interactive nature, have high requirements for network delay. The lower the time delay, the better the game experience, the higher the time, the worse the game experience, and even the normal game. Therefore, time delay is an important indicator for evaluating the networking performance of smart phones. There are many reasons for delay. Because IEEE802.11 is the MAC layer and physical layer protocol under the TCP/IP protocol, the CSMA/CD conflict avoidance mechanism is adopted. Therefore, the delay of WiFi wireless network is mainly caused by the poor signal quality or the interference caused by other WiFi devices. The poor performance of the receiver can also lead to a downward retransmission.

One of the most important reasons for the interference between mobile phones and WiFi signals is the interference between adjacent channels. This interference is mainly caused by the leakage of adjacent channels, and the adjacent channel leakage ratio (ACLR) reflects the energy ratio of the cell transmitter signal to the adjacent channel. The higher the ratio, the greater the interference in mobile phone signals at other frequency points. If the cell phone's adjacent channel is not well contained, the interference of the environment will be great, and the retransmission of the whole network will increase, resulting in delayed increase and decreased throughput. In the 802.11 standard, mainly through the emission spectrum template (Transmit Spectral Mask) to performance evaluation of mobile phone signal spectrum. We need to evaluate this target by testing the test equipment's spectrum launch template test function to ensure that the product can minimize interference with adjacent channels in actual work.