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Whats_New_in_Core_Bluetooth.md

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WWDC 2017

Table of Contents

What's New in Core Bluetooth - Thursday

Session video and resources: https://developer.apple.com/videos/play/wwdc2017/712/

Enhanced Reliability

  • Backgrounded apps
    • iOS Apps can continue using Core Bluetooth in background - Finally !
  • CBCentralManager Restoration
    • Will look for devices to keep the connection established continuously

State Preservation and Restoration

  • Work across device reboot or Bluetooth system events - Even after a reboot connection will be preserved
    • This is trying to ask for as few system resources as possible

Write Without Response

  • Write without response would be dropped due to memory pressure
  • New property will tell your app if more data can be set

Platform Support

  • watchOS 4 is now supported which will eliminate the need to bring out your phone
  • 15 ms minimum connection interval
  • State preservation and restoration on iOS
  • tvOS
    • Foreground app only
    • Central role only
    • Minimum 30 ms connection interval
  • watchOS
    • Access dictated by system runtime policies
    • Same things for tvOS applies to here
    • Supported on Apple Watch Series 2

L2CAP Channels

  • L2CAP Channels -> stream of data between devices
    • First time we can use them
  • Peripheral side L2CAP
    • Listen for incoming L2CAP Channels

Best Practises

Time to Discover

  • Use the shortest advertising interval possible
  • Optimize for when users are trying to use your accessory
  • See the Bluetooth Design Guidelines for power-efficient advertising intervals

Reconnecting devices

  • No need to scan for a peripheral for reconnect
  • Retrieve the peripheral and directly connect

Service Discovery Speed

  • Use as few services/characteristics as possible
  • Group services by UUID size
    • Group 16 bit and 128 bit services together to get the most out of one badge in one time
  • Support GATT Caching
  • Use "Service Changed"

Getting the most out of Core Bluetooth

  • Write without response - again
    • Use all available connection events to transmit
    • Takes advantage of larger Connection Event Length

Extended Data Length

  • New Feature in Bluetooth 4.2
  • Much larger packets
  • Throughput (kbps) is increased from 2.5 to ~400 !!!

Summary

  • Request a shorter connection interval
  • Update to latest BLE

Key Takeaways

  • Check out State Restoration
  • Expand your app to tvOS and watchOS
  • Use L2CAP for stream protocols or large data transfers