AirPods - How did Apple do it? | Cambridge Consultants: The easiest way to get the audio to your second AirPod is to use Bluetooth forwarding. This is a tried and tested approach between two Bluetooth devices. It requires no extra hardware, no additional stack or software support for a new protocol. However, Bluetooth cannot pass through the head, and Bluetooth waves cannot be made to go around the head. This does not mean that this approach doesn’t work. In fact for indoor radio use, radio waves reflect off objects, walls and ceilings, creating a path for Bluetooth to travel from one AirPod to the other. Performance outdoors is a different matter. To put it mildly, performance may vary, and is likely to be extremely poor in the middle of a large grassy lawn for example.
A second very popular approach is to use Near Field Magnetic Induction (NFMI), an approach similar to induction loops for hearing aids. This approach works in all environments, as it uses magnetic signals that go through the user’s head with minimal loss. Unfortunately, they operate at completely different frequencies to Bluetooth and require very sophisticated RF design to fit into such a small form factor. The additional RF front end, software requirements, and antenna design make this a less attractive option and less likely to hit the aggressive power targets that Apple has set out.
In fact, fitting a Bluetooth and NFMI radio on such a small form factor as the W1 chip, and ensuring antenna performance in such as small form factor as the AirPods, makes NFMI an unlikely candidate for Apple’s end design.
We don’t yet know how AirPods perform for people in open spaces, and we will have to wait and see if Apple has managed to tackle this issue. A Wall Street Journal writer, writing a generally positive review of preproduction units said “…I experienced a few drop outs on my AirPods outside” . However, we can speculate as to what Apple could have done to make a pure Bluetooth solution work for them.
I suspect that Apple combined a fully standards compliant and existing solution based on Bluetooth forwarding (with all of its interoperability benefits and performance drawbacks) with a proprietary approach when using the latest iOS devices to solve the existing solutions problems.
Apple have probably done the smartest thing an engineering team can do when faced with a very hard challenge – step back and find another way round it. We do this constantly here at Cambridge Consultants. Sometimes the hardest problems can be overcome by our interdisciplinary teams by focusing on the end goal and finding all the different ways it could be achieved instead of focusing on that massive obstacle that one of the ways has presented us with.
So how do you send music from one side of your head to the other, through your head in the simplest, fastest to market, and most robust way?
A second very popular approach is to use Near Field Magnetic Induction (NFMI), an approach similar to induction loops for hearing aids. This approach works in all environments, as it uses magnetic signals that go through the user’s head with minimal loss. Unfortunately, they operate at completely different frequencies to Bluetooth and require very sophisticated RF design to fit into such a small form factor. The additional RF front end, software requirements, and antenna design make this a less attractive option and less likely to hit the aggressive power targets that Apple has set out.
In fact, fitting a Bluetooth and NFMI radio on such a small form factor as the W1 chip, and ensuring antenna performance in such as small form factor as the AirPods, makes NFMI an unlikely candidate for Apple’s end design.
We don’t yet know how AirPods perform for people in open spaces, and we will have to wait and see if Apple has managed to tackle this issue. A Wall Street Journal writer, writing a generally positive review of preproduction units said “…I experienced a few drop outs on my AirPods outside” . However, we can speculate as to what Apple could have done to make a pure Bluetooth solution work for them.
I suspect that Apple combined a fully standards compliant and existing solution based on Bluetooth forwarding (with all of its interoperability benefits and performance drawbacks) with a proprietary approach when using the latest iOS devices to solve the existing solutions problems.
Apple have probably done the smartest thing an engineering team can do when faced with a very hard challenge – step back and find another way round it. We do this constantly here at Cambridge Consultants. Sometimes the hardest problems can be overcome by our interdisciplinary teams by focusing on the end goal and finding all the different ways it could be achieved instead of focusing on that massive obstacle that one of the ways has presented us with.
So how do you send music from one side of your head to the other, through your head in the simplest, fastest to market, and most robust way?