A startling difference between Apple and Android devices is highlighted in an analysis by Cambridge Consultants. While the report examines previous generations of devices and operating systems, it highlights the importance of accounting for a wide spread in designing Bluetooth LE experiences.
Updated: With feedback from the whitepaper author, we’ve corrected this post to reflect that Nexus is by far the best performer in this test.
Connection Attempts Can Drain Battery on Galaxy S4
A significant difference in number of connection attempts could result in a visible drain on battery (emphasis added):
The figure shows that an accessory device optimised for the lowest average number of connection attempts for the Nexus (4 attempts) would, on average, require an incredible 95 connection attempts to connect to the Galaxy S4. Assuming again that ‘connecting’ consumes 82% of the total radio power budget, this means that one user gets a battery life of 2 days, and another gets over a month.
In one part of the analysis, which compared the ability for a Bluetooth LE ‘beacon’ to connect to a phone where the app is in background mode, compared a LG Nexus 4 running Android 4.3, Samsung Galaxy S4 running Android 4.2 and Apple iPhone 4S running iOS v6.
In this analysis, they assessed the number of attempts the beacon would need to take in order for the phone to recognize the beacon in background mode.
While the Nexus outperformed the Apple 4S, it was negligible when compared to the underperforming Galazy.The report was recently updated to include Android 4.3 but they are still conducting analysis on KitKat and iOS7.
And the OS Counts! But Not How You Might Think
In a previous part of their study, they compared the difference between OS5 and 6 for iPhones and actually saw a degradation:
The average number of connection attempts when transmitting at 80ms intervals increased from 20 when connecting to an iPhone running iOS v5 to 27 when connecting to the same phone running iOS v6. This variation would cause a 35% increase in the total power the accessory device used to connect to the smartphone purely due to the user upgrading the operating system.
Advice for Manufacturers
However, the general findings of the report point to good advice to the makers of beacons and Bluetooth LE capable accessories:
To maximise the user experience of a product, devices need to be designed to optimise the connection parameters for the specific use case. In addition, devices should be architected such that they can change the way they connect with a smartphone as operating systems and handsets evolve. This approach will enable the leading device makers to establish market-leading products that can maintain their performance over time despite their dependence on the smartphone manufacturers.
Key to enabling the leading players to stay ahead will be an ability to quickly characterise new operating systems and handsets and to analyse the impact of any changes on their products. This detailed knowledge of how the smartphone is behaving is not publically released by the smartphone manufacturers and so understanding this offers a competitive advantage to accessory developers.
Download the full report at Cambridge Consultants.
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