How to increase Bluetooth communication speed in swift? - ios

I have an iOS application which communicates with an BLE device that requires the lowest latency.
The manufacturer of the BLE device specifies that connection interval supported by the device as follows.
#define MIN_CONN_INTERVAL MSEC_TO_UNITS(7.5, UNIT_1_25_MS) /**< Minimum acceptable connection interval, Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL MSEC_TO_UNITS(30, UNIT_1_25_MS) /**< Maximum acceptable connection interval, Connection interval uses 1.25 ms units. */
Manufacture of BLE device ask to usa a minimum connection interval of 11.5ms in the iOS code.
This is the first time I hear about changing connection interval. But after some research, it seems that the device that initiate the connection can request for a better interval.
(https://devzone.nordicsemi.com/f/nordic-q-a/6500/not-clear-about-minimum-and-maximum-connection-interval)
However I can't find a way for my iOS Bluetooth manager to ask for a better latency. Is this even possible in iOS?
EDIT: I forgot to mention that the device is a BLE Midi device. I don't know if that can help for improving the latency.
Sincerely,
Jery

Apple only offers Bluetooth LE to developers, which is much slower than standard Bluetooth.
With that said, you can access the faster Bluetooth in iOS by joining the MFi program and writing Apple a check for the ability to do so.
This section from the MFi FAQ gives some clarification on the issue from Apple:
I want to develop an accessory that communicates with an Apple device
using only Bluetooth Low Energy. Do I need to join the MFi Program?
No. Accessories which connect to an Apple device using only Bluetooth
Low Energy/BLE/Bluetooth 4.0 or standard Bluetooth profiles supported
by iOS are not part of the MFi Program.
So in other words, to use Bluetooth EDR, you must join MFi.

Related

is there any limit, BLE peripheral devices for Services and their characteristic in iOS swift?

Actually, I am getting some problems after adding one more service in the device firmware.
is there any limitation in ios for BLE Hardware device to have maximum Services and their characteristics for iOS device read-write operation?
According to Theories, there is no limit to the number of Bluetooth LE devices that can be connected to a single iOS device and you can use unlimited services of single.
In practice, however, the limit seems to be somewhere above 20 LE devices being connected simultaneously to the iOS device. That number comes from both Bluetooth LE transmitter manufacturers and accessory developers that I've talked to. The exact figure will probably vary based on the particular iOS device involved and the transmitting properties of the Bluetooth LE accessories.
i hope it will be informative for you :)

Ios BT Connectivity & Raspberry Pi

I have a idea that requires connecting an ios device to a Raspberry Pi without the end user having to do anything special. The device will not be connected to an existing wifi network so BT or wifi hotspot seem to be my only options, BT preferred.
I'm aware that Apple does require some sort of BT hardware approval which I wont have I'll be using generic BT hardware. Once a connection is established I then want to be able to request data or call API's running on the Raspberry PI.
Does any of this sound achievable and are there any links that may help.
There are two flavours of Bluetooth: the so-called Bluetooth Classic, and the newer Bluetooth Low Energy (also called Smart Bluetooth or Bluetooth 4.0, though this is actually incorrect as BT 4.0 includes both Classic and Low Energy).
On iOS, Bluetooth Classic devices do indeed need to go through specific processes (MFi), or use an existing BT protocol supported by iOS to be used.
However, you can connect to any Bluetooth Low Energy (BLE) device, without any need for MFi, approval, or support by iOS. This is done though the Core Bluetooth framework.
As long as Bluetooth is enable in the iDevice, you can connect to a BLE device without any user interaction (though UX usually dictates doing so, so a user can actually select a specific device if there are many "matching" devices in range).

iOS device communication with bluetooth enabled device

I have a specific requirement to communicate an iOS device with a wifi/bluetooth enabled device. At this moment, I'm confused with some points and requires an expert advice.
Can I use adhoc wifi method for communicating? but in this case, can I connect to another network? On my research, I found no so I'm opting for Bluetooth.
If I go in bluetooth communication,
Do the device need MFI licensing or can we use classic bluetooth?
From few blogs I found out that Bluetooth low enrgy devices with 4.0 can be used to communicate with ios without licensing. Will this work?
PS: My requirement is to send strings of data to and fro from the ios and other wifi/bluettoth enabled devices.
An iOS device can only be connected to a single Wi Fi network at a time, so an Ad-hoc network connection probably won't work for you.
If you join the MFi program you can use the Wireless Accessory Configuration (WAC) feature to simply the process of connecting your device to the user's existing network.
If you use Bluetooth Low Energy/Bluetooth Smart/Bluetooth 4.0 then you don't need to go through the MFi program, but you are limited to iPhone 4S and later and iPad 3 and later. If you use "classic Bluetooth" (Say Bluetooth 2.1 Serial Port Protocol) then it will work with all devices but you need to go through MFi.
Bluetooth Low Energy isn't great for high data volumes (say video streaming) but is fine for smaller amounts of data (you talk about "strings" so it will probably be suitable for you).
The other advantage of BLE is that it is independent of the iOS device's Internet connection so the user can cary the BLE device around and maintain communication regardless of their WiFi connection.

Can you pair a bluetooth LE device in an iOS app

Can you pair a bluetooth LE device in an iOS app, i.e. not via Settings. Trying to make it easier on the user to pair with a specific device.
If so how?
You don't pair Bluetooth LE devices through system settings. Generally you don't pair with Bluetooth Low Energy devices at all. The only time that pairing is required is when the device has an attribute that is marked as encryption required - attempting to read this attribute will trigger a pairing process, but before you can read you need to discover and connect to the device.
Discovery and connection is handled by the Core-Bluetooth framework.
The Core Bluetooth Programming Guide goes through the steps required to use a CBCentralManager to discover and connect to a BLE peripheral.
According to the BT SIG Security Manager documentation you can pair/Bond ble devices if they respond to the message that is.
You can also wait and do it as previously explained from the peripheral side. Some devices like HipKey does this automatically when connecting first time.
Look at BTSIG Security Manager specifications.
On Android this also works from BT settings menu IF the peripheral supports it.
Bonding and Authenticating are usually confused but om most platforms it means the same.
A good way to try this out is by buying the TI ble development kit. Its cheap. It comes with a USB dongle and SW which can be used to initiate pairing like from the settings menu.
To do it from iOS just connect and read a known encrypted characteristic.
Cases where you want to "pair" (remember a Bond) includes Pulse meters, hearing aid, keyboard and other private units.

iOS Bluetooth dual-mode; connect BLE (GATT) to an already connected BR/EDR (A2DP/HFP) stereo headset simultaneously

I'm developing a stereo headset with Bluetooth using the classic profiles (HFP, A2DP, AVRCP) as one would expect Ina stereo headset. However, I want to deploy a remote control app for iOS, and use it simultaneously to the other classic links, but the dual-mode chipset I'm working with in my design does not behave as I'd expect;
The headset is setup as a peripheral, letting the iOS device act as central. As such, the peripheral advertise its BLE services (with my specific 128-bit UUIDs) and all is good. I can browse the peripheral from any central, but only when I'm not connected with classic profiles (e.g., while not streaming audio).
My device does not seem to be able to advertise BLE, while connected with HFP and/or A2DP! However, I have seen demos of the same chipset acting as BLE central, scanning and connecting to other BLE peripherals, while simultaneously streaming audio via A2DP. However, in that setup the device was acting as A2DP sink connected to an iPhone, while scanning/connecting via BLE to a third unit acting as BLE peripheral. Hence, not point-to-point with both Classic and Smart Bluetooth to the same device.
Is there a dual-mode constraint that one cannot act as peripheral while supporting/connecting to Bluetooth Classic profiles? And that only Central-mode is supported in that case?
FYI, I'm using CSR's 8670 chipset.
UPDATE
New answer added. My apologies for not clarifying/cleaning-up my previous answer until now -- time flies!
Well, after digging down into specs and trying to understand things more clearly, I've found the answers I was looking for, even though I would have preferred to more optimistic answers... ;(
Nevertheless, let's get to it; the Bluetooth spec for 4.0 (BLE) says that;
Dual-mode gadgets cannot act as BLE peripheral and advertise its
presence while still being connectable in "Classic" Bluetooth using
BR/EDR.
Furthermore, CSR source-code examples for the CSR8670 dual-mode chipset I'm using all behave in the same say; BLE advertisements as peripheral are disabled when any classic BT-link is connected. Instead, the CSR source code promote that the device should act as the BLE central instead, allowing other BLE peripheral units to advertise and connect to it, all fully doable while streaming audio (acting as A2DP sink).
This does not suite my setup at all since;
BLE centrals consume more power than BLE peripherals, and my device needs to conserve energy
The dual-mode "combo"-problem of combining a BR/EDR-device with BLE peripheral functionality just moved to the phone instead, which will not work any better since we cannot expect Apple (or anyone else) to violate the BLE spec.
Instead, the recommended approach is let my stereo headset skip BLE entirely and use GATT over BR/EDR instead, also known as advertising via "vanilla", which makes sense really; I mean, I already have an ACL-link setup between two devices, why should I need to kick any sort of discovery mechanism?
Again, the Bluetooth SIG comes in handy;
https://developer.bluetooth.org/TechnologyOverview/Pages/GATT.aspx
GATT and ATT are not transport specific and can be used in both BR/EDR
and LE. However, GATT and ATT are mandatory to implement in LE since
it is used for discovering services
So, the SIG says "yes" to using BR/EDR as transport for GATT, but the question then instead becomes; how can I then get access to that connected BR/EDR device from within my iOS-app, where the typical scenario is to use CBCentral to scan, discover and connect to a CBPeripheral? The answer is simple; you cannot, since iOS 7.0 does not (yet?) support GATT for BR/EDR;
https://www.bluetooth.org/tpg/showDeclaration.cfm?3A000A5A005C5344535D5414403B0C0D0E2405022413010E57503F202A5A72
So, to sum things up; if you want to have a peer-to-peer setup between two dual-mode Bluetooth devices, using BOTH Bluetooth Classic profiles AND Bluetooth Smart services/characteristics, you should use GATT over BR/EDR, which is no-go for Apple-devices, but might be supported by Android (don't know, will port app to Android eventually though, but regardless it's not a big deal for Android since worst-case will imply a fallback to SPP and a simple byte-protocol to do the work that I need to get done).
That's that. Hope that I've helped someone ;)
/Markus
You learn as long as you live, I suppose, and this question's answer is NOT that it's not supported which I claimed earlier (based on what I thought I knew).
The short and clean answer to dual-mode and headset development on CSR-chipsets is simply that it was a constraint in the CSR bluetooth stack on earlier SDKs.
The Bluetooth SIG has never not supported dual-mode acting as Peripheral while being connected via classic links to the same device. On the contrary, it clearly spec. how such interoperability should be carried out -- but that doesn't always mean that all BT-stack implementations out there are capable of such functionality.
Hence; Using the latest devtools and the latest Bluetooth firmwares/stacks from CSR has resolved all issues and dual-mode is now fully, and actually quite nicely I might add, supported on the CSR8670/75 chipsets.
I am also using the CSR8670 device.
It have it working. Both a BLE peripheral and audio.
You need to be using ADK 4.0.0 by CSR.
Bluetooth 4.1 and Bluetooth 4.0 are different. For what you said about Bluetooth 4.0 is correct, but your chip can do Bluetooth 4.1.
4.1 allows such connections.
I also added "Dual mode" flags to the advertising packet.
There are a few conditions, such as a connection Interval of at least 90 miliseconds highly recommended so you dont mess with the audio.
Good luck!

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