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The Persistence of Quality

The Swiss’ dedication to quality has won their watches a global reputation for over a century. Originality can be seen among every watch, each with its own unique design. Each component of Mercedes Benz is created to perfection, building worldwide trust on this brand. Further, Nintendo Game Boy is popular around the world for its emphasis on user experience… As the leading manufacturer in the wireless network field, Huawei follows strict quality standards for all its products in all aspects, from product design to component selection, and from reliability verification to performance test. Huawei’s persistence of quality helps create classic Wi-Fi products for enterprises in various industries.

Design: No Room for Faults and Defects

AP is an important device that works on the access layer of a wireless network. Take apart an AP, and you will find that thousands of components are scattered on the board like stars, seemingly in disorder, but in fact well-placed. Among all the components, the RF chip is the main unit for AP to process all wireless data. Therefore, it is not an overstatement to call it the ‘heart’ of the AP. An unnoticeable small unit working with the RF chip, known as crystal resonator, is called the ‘heart’ of the chip by professionals.

In 2015, when Huawei developed a commercial 802.11ac Wave 2 product, it found the problem of overheating and high power consumption brought by heavy data traffic: the highest temperature of a chip surpassed 100°C. In such case, the crystal resonator, whose standard working temperature was 85°C, would become faulty even before the due time. This became a big problem of the product. Having negotiated with the chips manufacturer, Huawei designers found that it was hard to purchase the crystal resonators with 100°C of standard working temperature in bulk, which meant the quality and lifespan of a product would be greatly affected because of this small chip. It is Huawei policy to never release products that have potential risks. Therefore, the designers redesigned the original plan, and solved the problem of overheating by cooling the chips at a faster rate. In twenty days of adjustments and tests, the highest temperature of chips decreased from 105°C to 100°C, and to 90°C, and finally to 85°C. The potential risks of the crystal resonator were avoided, and AP’s quality was guaranteed.

Besides the design, Huawei is also particular with the choice of components. Because of this, Huawei is both loved and hated by the component suppliers. They love Huawei because Huawei is both willing to make sacrifices in bidding, yet never gives in when it comes to the performance and reliability of components; they hate Huawei because it is willing to discontinue production of products with even the smallest faults.

Reliability Standards: 10% More than Excellence

“High standards make common goods; medium standards make defective goods; low standards make nothing.” If the excellent goods are the goal, higher or even ‘extreme’ standards must be adopted. In popular words, 10% more than excellence.

20°C-higher Standard Ensures Products in Harsh Conditions

At the beginning of 2015, a famous air conditioner manufacturer came to Huawei, hoping to have a Wi-Fi device that was resistant to the high temperature of 50°C in the air-conditioning test workshop. This is not an easy requirement. This client had adopted another manufacturer' Wi-Fi device before, which was supposed to work well in 50°C condition, but experienced abnormal restart and decreased rate in the first month.

This failure was caused by lower industry test standards and less strict design. For the test in high and low temperature, the common method is to place an AP in a constant temperature chamber to be cyclically tested for 7x24 hours. If no faults occur in the whole duration, the AP is deemed to meet the requirements. Take the example of indoor AP:

The highest temperature that an AP can function is usually 50°C, and the standardized method is to set the temperature of the constant temperature chamber to 50°C. At the end of the test period, if the AP still works well, the high-temperature test is considered successful.

But Huawei has higher standards: it raises the highest temperature by 20°C, and extends the temperature range to –40°C to 70°C. The time duration for the test is 15 days. Only when all samples are tested normal can the test be successful. Such long-duration test of large samples can expose design problems, potential bugs of the components, and processing problems. With these problems solved, the products will be better refined and more stable.

Apart from temperature tests, to improve the operating reliability of a product, Huawei also has its APs to be tested for electromagnetic compatibility, Production Compliance, gas corrosion-resistance, salt spray resistance, wind resistance, ice resistance, dust resistance, and water resistance. There are in total 44 big tests and more than 1000 small tests, and every test is required to meet or even surpass industry standards.

The constant temperature chamber for temperature test

12 GHz Wider Frequency Range Makes Global Products

Electromagnetic Compatibility (EMC) standard is an evaluation of the electromagnetic interference and anti-interference capability of electronic products. It is one important indicator of product quality. Faced with a global market, Huawei Wi-Fi products are required to meet not only the EMC Standard of China, but also the CE of the European Union and the Federal Communications Commission (FCC) standard of the United States. These two standards are accepted by 90% countries in the world. Take Radiated Emission (RE) of EMC test as an example. The Chinese standard states that the frequency range of 30 MHz to 6 GHz is suitable, whereas the FCC requires a frequency range of 30 MHz to 18 GHz, 12 GHz more than Chinese standard. This standard prevents the interference of Wi-Fi products to other high-frequency electronic products. In terms of human health, FCC standard requires the tested products must comply with Class B standard, which is three times stricter than the generally-accepted Class A standard. Wi-Fi products that can pass FCC tests are therefore much safer to human health.

Besides this, to ensure that the device is harmless and stable, every Huawei Wi-Fi device is required to pass Production Compliance tests, which are much stricter than industrial standards. Take the drop test in mechanical strength test as an example: in a usual test, packaged devices are dropped from 1 m high; while in Huawei’s test, the height is 1.5 m, and unpackaged devices are also required to be tested. This design considers the dropping scenarios during transportation and installation. A small modification to the test method brings a lower fault rate and higher reliability.

An Extra 15 Minutes Ensures Qualified Products in Extreme Conditions

As outdoor APs usually work in open-air environment, the water proof, dust proof and lightening proof performance is an important key performance indicator (KPI). Generally, outdoor APs have good dust-resistant and water-resistant performance when at the IP67 protection level. Dust-resistance at the level of ‘6’ means not a speck of dust can get into the device; water-resistance at the level of ‘7’ means the device can still work after thirty minutes’ soaking in the water. However, the test standard for thirty minutes’ soaking is not applicable for the devices placed in rainy places. So Huawei extends the soaking time to 45 minutes — quite an extreme condition to test the water-resistance performance of APs.

Huawei APs test method

Test Environment: Much Stricter than Industrial Standards

Huawei puts a great emphasis on product test. To ensure the excellent performance and stable quality of every product, the standard for each test procedure is much stricter than industry standard.

Compatibility Laboratory Covering 80% of Operation Systems and Chips

The statistics show that to this day there are more than one hundred famous smartphone brands in the world. Though the top 10 brands take 80% of the market share, the Wi-Fi performance of every single STA varies between brands and operation systems. To guarantee good access experience for different STAs in Wi-Fi networks, interconnection with STAs of different brands must be tested. This is called the STA compatibility test. The quantity and brands of tested STAs are the top priority of the test.

To guarantee good STA compatibility with Wi-Fi networks, Huawei Suzhou research institution invests heavily to build the best equipped laboratory for STA compatibility.

  • Brands and Quantity: more than 140 STAs from 20 main brands that take up 90% market share, as well as mainstream STA types and operation systems in the recent 3 years.
  • Brands: top 10 brands in the world and main brands in China, including Apple, Samsung, Huawei, Xiaomi, Lenovo, Coolpad, Vivo, HTC, LG, Meizu, Sony, TCL, ZTE, YotaPhone2, and Blackberry.
  • Chips: main chips providers who take up 95% market share, such as Broadcom, Qualcomm, Marvell, and Ralink.
  • Operation Systems: main operation systems, including Windows, iOS, Android, and Symbian. At least five versions of each operating system are selected.
  • STA Forms: tablet, mobile phone, notebook, wireless phone, wireless NIC, and STAs used in special industries.

As for the test items, besides the basic items (for example, access, STA performance, authentication and encryption, and roaming), band steering and Bring Your Own Device (BYOD) that are essential to a good user experience are also added to ensure perfect experience for any user with any STA in a Wi-Fi network.

Different STAs

Simulate Real Mobile Experience Test Environment

The popularity of BYOD has lifted people from their seats. Despite the convenience, signal interruption can occur when users are moving. For example, a call while driving or a mobile STA’s access to a Wi-Fi network may be interrupted. To ensure the best Wi-Fi performance in mobile scenarios, repeated tests are required so that technologies and network deployment can be improved.

Huawei Suzhou research institution has built a professional mobile experience test laboratory. In this laboratory, manual test is replaced by smart robots. The robots can simulate people’s moving paths and walking speed, and roam irregularly; at the same time, the robots with multiple STAs can simulate voice and video interactions in real time to test the network’s compatibility with different STAs. This can simulate the BYOD office environment of an enterprise.

In each test, the robot carrying various STAs moves irregularly in an area of about 200 m² for more than one hour, triggering more than 200 roaming actions. This is to test the STAs’ handover performance between different APs. During the test, the STAs placed on the robot also make video calls to test the roaming performance of mobile STAs. The test succeeds only if the video calls are not interrupted and services are stable throughout the more than 200 roaming actions within one hour.

The smart robot for mobile experience test

Multi-user Service Test Environment Based on Models of World’s Top Stadiums

Signal Iduna Park in Dortmund is the biggest stadium in Germany, accommodating 73,000 spectators on average, and with up to 21,000 spectators’ accessing the Wi-Fi network in peak time. Beijing National Stadium, or Bird’s Nest, is the biggest steel-structured stadium in the world and can accommodate 91,000 spectators. In the 2015 IAAF World Champions, this stadium had 12,000 spectators on average; CCTV Headquarters is the biggest wireless office building in Asia, and there are more than 10,000 employees working on the move each day. The former two buildings have the highest access density: more than sixty STAs access a single AP concurrently; the latter building is a symbol for multiple services: the network has to provide a bandwidth of 2 Mbit/s per-user, and carry web browsing, video, and voice services concurrently.

In regards to the access density of Signal Iduna Park, Huawei engineers deployed three 802.11ac APs in a laboratory of 100 m² to carry out density test with 220 STAs; at the same time, by referring to the wireless workspace in CCTV Headquarters, there are 80 STAs playing video, 130 STAs downloading and browsing webs, and 10 STAs having voice calls. The test is divided into three phases, and each phase is conducted based on the former phase. In each different phase, traffic volume and service types are added to adapt to different service environments. Finally, these procedures are applied to the multiple-user service test. Through this test method, Huawei creates excellent user experience.

Multi-user service test environment

Super Tester That Simulates 100,000 STAs’ Concurrent Access

One of the biggest challenges in high-density scenarios is the AC performance when a large number of STAs go online concurrently. This is common in places with large crowds and frequent authentications such as schools and stations. But in laboratories, testing for large number of STAs’ access is impossible. Therefore, Huawei has developed a ‘super tester’ to test the concurrent processing capability of ACs for access authentication. One port of this tester can simulate the environment of 1,000 APs and 10,000 STAs, and the entire tester can simulate the environment of 4000 APs and 100,000 STAs, that is to say, a football field of 100,000 spectators is moved into the laboratory. In one second, a port can provide concurrent access to 500 STAs, or 300 roaming STAs, which simulates scenarios where a Wi-Fi network that provides access to 100,000 STAs in 200 seconds when spectators enter the stadium.

Accumulation is Essential for Success

In July of 1999, Huawei had its first Wi-Fi network patent. Since then, Huawei has been developing Wi-Fi products for seventeen years, won more than 2000 patents, and served more than 1000 customers. Huawei Wi-Fi technical expert, Doctor Osama Aboulmagd, is now the chairman of IEEE 802.11ax TG, and is leading the plan for the next-generation Wi-Fi standard. In 2015, Huawei caught the attention of Gartner and IDC: it became the only Chinese competitor of Gartner MQ and the main partner of IDC MarketScape.

With the accumulation in wireless technologies, top-class experts all around the world, and continuous investment in R&D, Huawei keeps its leading role in the industry, and will continue to strive in the Wi-Fi market.

By Kong Weihua