Re: Bluetooth Low Energy Throughput and Rate Limiting
Re: Bluetooth Low Energy Throughput and Rate Limiting
- Subject: Re: Bluetooth Low Energy Throughput and Rate Limiting
- From: Etan Kissling <email@hidden>
- Date: Fri, 14 Jun 2013 09:07:29 +0000
- Thread-topic: Bluetooth Low Energy Throughput and Rate Limiting
Kendrick,
yes, Apple is limiting throughput by restricting the number of packets sent to
4 per connection event (officially 6 - see http://stackoverflow.com/questions/10354613).
My measurements at 37.50ms connection interval are as follows:
Indications / Read / Write With Response : ~4 kbit/s
Notifications / Write Without Response: ~20 kbit/s
Graph for Notifications: http://www.scriptreactor.com/conn_interval-throughput.pdf
When you go with Notifications / Write Without Response you need your own
protocol to offer reliability, as such packets may be dropped at any time.
Depends also on range and angles in which you hold the device.
Etan
On 14.06.2013, at 03:53, Kendrick Taylor <email@hidden>
wrote:
> I'm running some performance tests on Core Bluetooth for a project I'm
> working on. It seems like apple is rate limiting the BLE connection,
> even when the app is in the foreground. I've tried reading a
> characteristic repeatedly and the throughput drops from a max of 400
> bytes a second, to 10 bytes a second after 12 seconds. This is
> repeatable if I use indications, instead of reading a characteristic
> repeatedly. Anyone have any insight on this issue? I may need higher
> continuous throughput in bursts over 12 seconds for my project, but
> not consistently.
>
> Thanks for any insight.
>
> Kendrick Taylor
>
> --
> Kendrick Taylor
> Sano
> email@hidden
> sano.co
> 703.855.5608
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