Efficient data transfer in Android

1. Efficient Data
Transfer in Android
Ralph Pina

2. Topics
- Radio state machine
- Big vs small cookie model
- Best practices
- Analyze your data transfer
- Resources for those interested

3. Radio State Machine
Full power: Used when a connection is active, allowing the device to transfer data at its highest possible rate.
Low power: An intermediate state that uses around 50% of the battery power at the full state.
Standby: The minimal energy state during which no network connection is active or required.
- AT&T timing for 3G

6. And then… show the user

7. Bundle Data Transfers

8. More graphs!

9. Wow power!

10. Prefetch!
“The single most important
measure: transmit as much data as
possible in a single burst and then
end the connection.”
- AT&T Labs

11. Parallelize!
- Parallelize requests

12. Download Patterns!
- Optimize download patterns based on data
connection.
- Prefetch more in 4G since you have higher
speed and it takes more power for the antenna
to come back.

14. More stuff!
- In Android, use SyncAdapter. Let the OS do
the the sync!
- Variable data transfers depending on usage.
- Sync when device is connected to power.

15. How GCM Works
- Phone connected via TCP port 5228
- Periodic heartbeat keeps the connection alive.
15 min on Wifi and 28 min on cell

16. Cotap Device Msging?
- Build our own MQTT server - invented by
IBM, very low power/bandwidth
- Current examples:
Eclipse Paho
Facebook Messenger and main app

17. Show and tell
- AT&T ARO
- supports second rate OS like
iOS and WP8!
- Android Monitor - <sdk location>/tools/monitor

18. Resources/Citations
- AT&T: A Call For More Energy Efficient Apps - http://www.research.att.
com/articles/featured_stories/2011_03/201102_Energy_efficient?fbid=Fp7Al9yFu9_
- AT&T ARO: https://github.com/attdevsupport/ARO
- Android Root Push Notification Fixer: https://play.google.com/store/apps/details?id=com.andqlimax.pushfixer&hl=en
- MQTT in Android: http://mqtt.org/wiki/doku.php/mqtt_on_the_android_platform
- Facebook: Building Facebook Messanger - https://www.facebook.com/notes/facebook-engineering/building-facebook-
messenger/10150259350998920
- DevBytes: Efficient Data Transfers - Understanding the Cell Radio (8/21/13): http://www.youtube.com/watch?v=cSIB2pDvH3E
- DevBytes: Efficient Data Transfers - Analyzing Your Transfer Profile (8/28/13): https://www.youtube.com/watch?
v=cLqWYeQcG94
- DevBytes: Efficient Data Transfers - Effective Prefetching (9/4/13): http://www.youtube.com/watch?v=Rk1u7VVmadE
- Using connectivity patterns: http://developer.android.com/training/efficient-downloads/connectivity_patterns.html
- Using Sync Adapters: http://developer.android.com/training/sync-adapters/index.html

19. Resources/Citations
- DevBytes: Efficient Data Transfers - Batching, Bundling, and SyncAdapters (9/11/13): http://www.youtube.com/watch?
v=5onKZcJyJwI
- DevBytes: Efficient Data Transfers - Eliminating Polling with Google Cloud Messaging (9/20/13): https://www.youtube.
com/watch?v=cJbGK6cVmSM
- DevBytes: Efficient Data Transfers - Variable Update Frequencies (9/25/13): https://www.youtube.com/watch?v=9z1BfyqmsyA
- DevBytes: Efficient Data Transfers - Minimizing Payloads (10/2/13): http://www.youtube.com/watch?v=OfYLG6FXtqE
- AT&T Research - Tail Optimization Protocol: http://www.research.att.com/export/sites/att_labs/techdocs/TD_100036.pdf
- Google I/O 2014 App: https://github.com/google/iosched
- Analyzing ARO Data: https://developer.att.com/static-assets/documents/aro/ATT_ARO_Analysis_Guide_3-2.pdf
- LTE Long and Short DRX Cycles to Save Power: http://mobilesociety.typepad.com/mobile_life/2009/12/lte-long-and-short-drx-
cycles-to-save-power.html