Domain knowledge Mobile Device Testing

The test on mobile devices is divided into several phases: R&D test, factory test, certificate test and User trial test.

R&D test is the main test phase for mobile device, and it happens during the developing phase of the mobile devices. Usually, as same as software testing, we will also have some main test phase, such as unit test, feature test, integration test, system test, and field test. But the object of these testing is not limited within software. As you know, each of the mobile devices is a small system, just like a PC, and it is made up of hardware system, software structure, and also the mechanical design. So our test should cover all of the components. That means, our R&D test will contains HW testing, SW testing, and Mechanical testing. Meanwhile, every test phase will also contain every kinds of test, such as basic function test, performance test, interaction test, interoperation test, boundary test, stress test, and so on.
Firstly, as a communicate equipment, there are many standards made for the mobile devices. We must do many related test to ensure the mobile products meet the requirements of the standards. I will introduce the standards in detail later. Normally, the HW test contains RF testing, EMC testing, Antenna testing, Safety and Health testing, Audio testing, I/O connector testing, Power consumption testing, and Accessory testing. Here, I will give out a brief object of every test topic. And later, I will try to explain them with more detailed information.

RF testing is divided into two parts with transmitter test and receiver test. The purpose of the RF testing is to ensure that the transmitter/receiver of mobile devices can meet the requirements from standards or governments whenever in normal conditions or in extreme conditions, such as high temperature and high pressure. To do the RF testing, we need some test equipments to assist our testing and analysis, such as TS8950G from ROHDE&SCHWARZ company.

EMC is the logogram of electromagnetic compatibility, that means the mobile devices should not interfere other devices, and also, be interfered by other devices. So there are two parts need to be tested related to EMC. One is electromagnetic interference, named EMI also, that is divided into Radiated interference and Conducted interference; the other is electromagnetic susceptibility, named EMS also. For EMC testing, there are also strict requirements on test environment, such as screen room and anechoic chamber, and test equipments, such as TS9980 from ROHDE&SCHWARZ company.

Antenna of the mobile devices may be integrated in the mobile, or the antenna is separated from the device. And the antenna part will impact on the mobile devices with which bands the mobile will work on. The testing will focus on the sensitivity of the antenna, and some of the test will combined into RF performance testing, such as frequency stability.

As mobile devices are used by people, the impact on human health of mobile devices is always the hot topic. Many organizations and governments also made lots of standards to ensure this. Safety test and SAR value are two significant items to control the impact. EN 60950-1 describes the general safety requirement. And SAR is the Specific Absorption Rate â which is a measurement for the amount of RF energy absorbed by the body or the head when using a mobile device. Also special test equipments are needed for the test.

Since voice call is the main function for people to use a mobile device, the test on voice call performance can not be ignored. The standards from 3GPP have many requirements on the audio quality and test. So the audio test is a absolutely necessarily item during R&TTE and GCF certificate. The test also needs special test equipment.

When people want to buy a mobile device, the work time of the mobile device will impact on the decision to choose which product. We must do the power consumption test to ensure the mobile device can work within long enough time in idle mode or calling mode. Usually, we test this with electrical current in different mode. Then, we can calculate the work time.

All of mobile devices have the I/O connector to communicate with outside. Also this makes the mobile devices support many kinds of accessories, such as charger, car kit, headset, and so on. To ensure the usage of the accessories, we need do the test on I/O connector of the device, and also the accessory itself.

Of course, there are also other kinds of hardware testing, such as Bluetooth related or WiFi related testing. Those are special items for devices to support related functions. We can talk about them in specific posts.
The software testing is another category during the R&D phase. In fact, most of the test is related to software in latter R&D phase. This is similar to other kinds of software testing, but the software test on mobile device has some special aspects, since the mobile device will be used by person, and there are some fixed procedures according to custom. According to different layer of the SW, our test can be divided into MMI testing, applications testing, and protocol testing.

MMI testing means Man-Machine Interface testing. From the name, we can know this part is related to User Interface testing. There will be a UI specification to specify the UI requirements. This document will be the main base for our testing. The test methods are mainly focus on the user case from UI. Also if we divide the test into several parts, such as display and functions, to verify the functions for layers under display, we can develop kinds of tools to do our test automatically. The automation of the mobile device test is another big topic.
For application testing, there are more and more applications available in mobile devices along with the improvement of CPU process capability and memory. And the test methods related to these applications are different from each other. User cases are also the important way to test the functions. And as more and more companies are involved into mobile device developing, the interoperation test are more important to applications than before together with interaction test, that will impact the performance of the mobile device too. The test tools for applications are also different from each other.

Protocol test is another kind of software test. Since there are many standards need to be fulfilled, the protocol test will focus on verifying the consistence between the software and the standards. For example, 3GPP defines an along test specification named 51.010 for all GSM mobile device. If the GSM mobile device wants to be sold in markets, the manufacture need get the Type Approval from related qualified test lab. Maybe, in some countries, this is not required by the government, but this is also required by the operators or end users. The protocol test also needs the special test equipments, that are qualified by public forum or test lab, such as CRTUG from ROHDE&SCHWARZ and SAT from Anite company.

Another topic in R&D test is mechanical test. Mechanical test is maybe thought as a part of hardware test. But the object of the test is totally different. The hardware test normally is focused on the electric performance and PCB functions. But mechanical test will focus on the physical parts. Usually, the mechanical test includes pressure resistance test, high/low temperature test, tiredness resistance test, falling test, environment test, and so on. If the mobile device is flip phone, the life of flip is also needed to be test.

Factory test is also important and necessary for the manufacturer to deliver the qualified mobile devices. The factory test is a small set out of the R&D test. And the test methods are also different in factory test. The test should be simplified and automated. The main reason is that the factory test should be fittable to the pipelining procedure. The RF performance, environment test, and other hardware checking are the main contents of factory test.

The purpose of the Certificate test is to ensure that the product can meet the standards requirements. Usually, this kind of test should be performed by third party qualified test lab. The test results and report will be used to apply the certificate from government or public organizer. The test cases and test environment are all defined in documents, that are published to all of the mobile device manufacturers. Of course, the test in third party test lab will raise some cost. So, pre-certificate test will be planned inside of development team before the certificate test to ensure the pass rate. Certificate test focuses on protocol, RF conformance, Audio, EMC, SAR, and so on. Different country and different operater may require certificate. Then, the certificate test will be planned according to product target market requirements. There may be some field trial test during the certificate test. The test cases are also specified. Since more and more applications are available now, if the application has some kinds of protocol or HW requirements, related certificate may be required. WAP certificate and MMS certificate are examples.

Before the mobile devices are put into market, there may be the user trial activities available. The manufacturer chooses a special group people to perform the user trail test. People just use the mobile devices with their own custom. If they found any bugs, they would report them to the manufacturer.