All about the user with U-vMOS

Video on the move

Research by mLAB shows that 51.4 percent of mobile subscribers watch video between one and three times a day. YouTube corroborates this trend, stating that more than half of its users watch video on their phone. Meanwhile, an even greater proportion of Facebook users – 75 percent – watch videos on the go.

Despite this, no unified standard exists to evaluate user experience. At the 2016 Huawei Analyst Summit, Yang Kun, from the IP Multimedia Commission under the China Communications Standards Association, summed up the current situation: "Users don’t like frame freezes and erratic displays at a lower price, preferring instead to pay a moderate price for excellent quality. The industry needs a complete set of evaluation standards to measure video service quality scientifically. Researchers have evaluated video picture quality before, but only in lab conditions. It’s doubtful that this reflects actual user experience."

Traditional networks that center on capacity and coverage are no longer up to the job, not least because networks with good KPIs can still provide a bad user experience. Therefore, network construction must involve a unified standard for evaluating video quality from the user perspective. Operators must consider how to define and evaluate user experience and how to build and manage experience-centric networks given the increasing demands on network performance.

Huawei’s U-vMOS helps operators build video-centric mobile broadband networks that enable them to plan, measure, and optimize user experience.

U-vMOS: Subjective AND objective

ITU-T’s objective assessment model defines the conditions for objective experiments, as well as measurement methods and evaluation standards. Its subjective assessment model uses an algorithm to define a set of parameters based on objective inputs to estimate multimedia quality.

Using the ITU-T standard assessment models, Huawei identified the top three impact factors on which to base U-vMOS: quality, interactivity, and viewing experience. U-vMOS covers videos on demand (VOD) in mobile scenarios, live videos, and VOD services in fixed scenarios, and provides network indicators for each impact factor.

In partnership with Oxford University and Beijing University, Huawei mLab fixed three measurable qualitative network indicators affecting video experience: resolution, initial buffering delay, and stalling ratio. For quantitative measurements, they created a unified model that combines users’ subjective scores with the objective scores from perception measuring equipment. By applying machine learning for model training, the team devised a computational formula for U-vMOS in mobile scenarios. To measure experience, U-vMOS gives a score from 0 to 5.

U-vMOS smashes bottlenecks

To simplify video experience evaluation, Huawei developed three U-vMOS testing tools: a user-level test app, a network- level data analysis tool, and a U-vMOS SDK for integrating third-party testing tools.

The user-level test app SpeedVideo allows users to test the video experience on their smartphones. The app displays the U-vMOS score, showing users the network's current video quality and giving the option to improve the experience. Available on Google Play and the Apple Store, users in over 140 countries have downloaded SpeedVideo, creating over 700,000 test samples. 

Operators need to know whether users are satisfied with their video experience, and be able to identify what’s causing any problems. Therefore, they have to evaluate video experience on the entire network, which cannot be done using a DT tool because they can only test a limited number of samples for analysis. The network-level U-vMOS, however, can analyze every video service in an entire district. The Huawei iDART/PRS tool supports network-wide U-vMOS evaluation, and provides geographic displays and grid-level displays with 50x50 m precision based on measurement reports (MR) and call history records (CHR). This is a professional tool for identifying video experience bottlenecks and problem demarcation for analysis.

Operators have already started using Huawei’s U-vMOS SDK, which is designed for third-party testers and assessing OTT service integration. In January 2016, an operator in Nanjing used WorkTour – a drive testing tool with U-vMOS testing functions developed by DingLi, one of China's largest testing equipment manufacturers – to carry out U-vMOS testing on a commercial network in six different scenarios. The test results helped the Nanjing operator understand the user experience of its network for precise network optimization, and expanded tests are planned.

Covering all sides

The target of traditional MBB network construction used to be pipelines, but it’s now moved to core service experience. Huawei's Video Coverage planning method for MBB networks helps operators build ubiquitous HD MBB networks. It comprises three steps:

• Evaluate networks and set goals: identify key areas for network planning using quantitative measurement of mobile video performance and analyze video consumption habits using objective indicators. 
• Analyze gaps and causes: define problems and classify root causes in areas where video experience is poor.
• Implement solutions and optimize iteration: Perform coverage and capacity planning based on the causes of substandard results, including solutions such as carrier expansion, sector splitting, adding sites, and deploying new features. Iteration planning can continually improve network experience.

Video Coverage has been used for network construction across the world including Australia, South Korea, the United Arab Emirates (UAE) and Saudi Arabia. A leading UAE operator proposed a video-centric traffic strategy to provide a superior HD video experience, opting to use the U-vMOS evaluation system for analysis in target areas to provide 1080p online video services. 

After the mobile video solution was deployed, the proportion of grids with a U-vMOS above 3.8 increased from 60.9 percent to 82.4 percent. Initial video buffering delay was reduced by 0.49 s, fulfilling targets and improving user experience. As a result, data traffic consumption shot up by 38 percent within three months, and encouraged overall network improvements that have boosted other services. 

E2E mobile video for better business

Huawei's E2E mobile video solution features multi-carriers aggregation, 4x4 MIMO, and 256QAM advanced modulation techniques for increased last-mile capacity. A two-level TCP proxy reduces initial video buffering delay on the wireless and PS sides, while the distributed Content Delivery Network (CDN) cuts the distance between the content source and user. A video QoS mechanism ensures a good experience and minimally impacts other services, and medium and heavy video load scenarios prompt the load optimization function. Huawei's mobile video solution also supports network capability opening and fully flexible billing, helping operators and OTT players to collaborate and encouraging new business models. Operators can open up network information like available bandwidth for subscribers and their location information so OTT companies can accurately transmit suitable bitrate and deliver a much smoother video experience. 

Jiangsu Mobile worked with iQIYI to move the CDN downstream to the Evolved Packet Core (EPC) gateway and open up user location information, allowing the gateway to better carry location information using the HTTP header, so iQIYI could carry out precise CDN node selection. This doubled average user download speeds and boosted U-vMOS scores by more than 20 percent. 

With the flexible charging policy, operators can deploy different charging modes based on levels of video experience, video types, time periods, and content. For example, a combination of a free basic experience and charging for HD experience can attract more users to try a video service, while backward charging and targeted OTT plans can boost profits.

In the MBB era, video is gradually supplanting voice as a new core service for mobile operators. Huawei believes in openness and cooperation, and works with operators and partners in the video industry to build an internationally recognised evaluation system for video that’s agreed upon in the industry, optimize user experience, and safeguard operators' investments. Huawei strives to support operator and OTT cooperation by opening network capabilities, thus boosting the mobile video industry as a whole.