ACADEMIA

Metrico Wireless announced findings from "iPhone 4S: The Ultimate Performance Report," based on the company's patented technologies and methodologies used to evaluate over 700 devices for carriers and OEMs. The three carriers covered in the report -- AT&T, Sprint and Verizon Wireless -- each led in different performance categories, ranging from call performance to voice quality to data and web, and the iPhone 4S proved to be a capable video device regardless of the network it was on.

Immediately following the launch of the iPhone 4S in October, 2011, Metrico began measuring performance of these devices on key criteria including:

-- call performance (making and holding calls)

-- voice quality (handset, speaker, Bluetooth, in noise)

-- data performance (HTTP download, HTTP upload)

-- web browsing (page load time, page load reliability)

-- video performance (frame delivery rate, freeze, impairment, audio).

Metrico performed over 21,000 web page downloads, ran more than 8,000 data download/upload tests while mobile and while stationary, and generated approximately 6,000 voice calls, using the company's global measurement system platform. Metrico also utilized the ITU-T P.863 speech quality algorithm known as POLQA to compare voice quality across the three carriers' networks. This approach resulted in robust, objective and repeatable analysis of performance from the subscriber point of view, in laboratory and live network conditions reflective of typical usage.

Key Findings

-- Call success rates -- the ability to make and hold calls successfully -- were slightly better for the Verizon iPhone 4S than for AT&T and Sprint versions.

-- Sprint's iPhone 4S performs better than the other carriers in live network voice quality on the uplink, while AT&T's iPhone 4S takes the lead in live network voice quality on the downlink. However, the two carriers' results are comparable. Across the three carriers, when compared to 3G smartphones measured in each carrier's portfolio, the iPhone 4S is: among the top performers for speech quality in noise; average in speech quality over Bluetooth; and a below average performer in speakerphone speech quality.

-- The AT&T iPhone 4S outperforms its Verizon and Sprint counterparts in data download and upload speeds. Moreover, the AT&T iPhone 4S outperforms the iPhone 4 in download speeds by a considerable margin.

-- Web browsing is faster on the AT&T iPhone 4S than on the Verizon and Sprint versions. The iPhone 4S outperforms more than 70 percent of competing 3G Smartphone models tested on the three networks.

-- The iPhone 4S shows excellent data task reliability -- or the success rate of completing tasks -- on all three carrier's networks, with 100 percent or near-100 percent success rates in stationary downloads, stationary uploads and web page loads. The improvement gains in stationary download reliability over the iPhone 4 are dramatic for AT&T and Verizon.

-- When on the live network and playing a video clip through the web browser, the iPhone 4S showed comparable, high rates of video frame delivery across all three carriers. However, when playing a video clip through YouTube, video frame delivery rate dropped, although the subscriber is still likely to perceive good quality. In general, the iPhone 4S shows a very low rate of video freezes and impairments, and a very high rate of audio delivery, across the three carriers' networks.