How Web Pages Can Extend (or Drain) Mobile Device Battery Life

Dr. Angela Nicoara on mobile browser energy consumption and ways developers can minimize energy use through design.

According to recent Global Mobile Data Traffic Forecasts (PDF), the number of mobile-connected devices will surpass the world’s population this year, and by 2015, there will be 788 million mobile-only Internet users. A recent paper, “Who Killed My Battery: Analyzing Mobile Browser Energy Consumption (PDF),” pulled together by the Deutsche Telekom Innovation Center in Silicon Valley and Stanford University researchers and published in the ACM 21st International World Wide Web Conference (WWW 2012) proceedings (PDF), takes a look at the growing popularity of mobile web browsing and the effects on energy consumption.

I reached out to Dr. Angela Nicoara, senior research scientist at the Deutsche Telekom Innovation Center in Silicon Valley who worked on the project, to find out why mobile browser energy consumption is a growing concern and what developers need to know going forward. Our interview follows. Dr. Nicoara will present the researchers’ findings in the “Who Killed My Battery: Analyzing Mobile Browser Energy Consumption” session at the Fluent 2013 conference next week in San Francisco, CA.

Why is browser energy consumption becoming more of an issue with the growth of smartphones and mobile browsing?

Dr. Angela Nicoara

Dr. Angela Nicoara

Dr. Angela Nicoara: Despite the explosive growth of smartphones and growing popularity of mobile web browsing, their utility has been and will remain severely limited by the battery life. Smartphones’ energy constraints are here to stay, and as such, optimizing the energy consumption of the phone browser while surfing the Web is of critical importance today and will remain so in the foreseeable future.

Our research, “Who Killed My Battery: Analyzing Mobile Browser Energy Consumption,” has focused on solving two of the most important and difficult problems pertaining to energy consumption on smartphones: developing an infrastructure for measuring the precise energy used by a mobile browser to render web pages and developing techniques to offload browser-heavy computations to the cloud.

A fundamental challenge arises as a result of power inefficiency of mobile web browsers at popular websites (e.g., financial, e-commerce, email, blogging, news sites) and how much energy is consumed to render a particular web page. Our work is the first of this kind to show how the structure of web pages can impact battery usage in mobile web browsers. Our research in this area has influenced and will influence the computing industry through the design and implementation of an infrastructure for measuring the precise energy used by a mobile browser to render web pages.

Learn from experts at this free, live webcast.

Angela Nicoara

Who Killed My Battery: Analyzing Mobile Browser Energy Consumption

Presented by Angela Nicoara
Date: May 24, 2013 at 10am PT

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What tools and methods are used to measure mobile browser energy consumption?

Dr. Nicoara: We developed novel techniques and tools to precisely measure the energy needed to render individual web elements, such as images, JavaScript, cascade style sheets (CSS) and plug-in objects, as well as designed a system that has the potential to dramatically reduce energy consumption of smartphones.

Our results show that for popular websites, downloading and parsing CSS and JavaScript consumes a significant fraction of the total energy needed to render the web page. We also show that by redesigning websites, the energy needed to render web pages is minimized. Another fundamental challenge stems from estimating the point at which offloading browser computations to a remote server can save energy on the phone. Given the smartphone’s limited energy, there is a strong desire to minimize its work, which can be helped by performing expensive browser computations off the phone. We explored the possibilities that arise when offloading heavy computations to a server cloud to save energy.

While researchers assume that measuring the energy consumed by a mobile operation can be known using a high-level API for finding out the battery level, we pioneered another approach: providing support for obtaining very precise, fine-grained energy use by a mobile browser to render web pages by hooking an external high-precision digital power multimeter to an open mobile phone’s battery. Given the inadequate nature of the existing tools, we then advanced our research in this field, aiming to accurately model the power draw of the Android mobile platform.

How can developers put this information to use?

Dr. Nicoara: We measured the energy needed to render financial, e-commerce, email, blogging, news and social networking sites. The tools are sufficiently precise to measure the energy needed to render individual web elements, such as cascade style sheets (CSS), JavaScript, images, and plug-in objects. Using the collected data, concrete recommendations are made on how to design web pages so as to minimize the energy needed to render the page.

Our research findings can help developers overcome the resource limitations of smartphones, one of the biggest challenges faced by today’s mobile industry. It allows developers to easily design energy-efficient websites by following concrete guidelines and recommendations. With our research, the improved battery life from our technologies dramatically enhances the usability of mobile devices and impacts consumers’ daily lives.

This interview was edited and condensed.

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topic: Programming