All right. Hello, everyone. Welcome to the Connect series. My name is Adrian Fernandez, and I'm joined by my co-host, Nick Smith.

Hello, Adrian.

Hey, Nick. Good to see you, man. And good to see you, the audience. We're here to continue talking about technology that TI is bringing to the table to help developers innovate when creating connected applications. And today is no different. We're bringing on Alexis Rodriguez from our SimpleLink hardware applications team to introduce a brand new topic here called coexistence. So really excited to learn more about it, and Alexis, thank you so much for joining us today.

Awesome. I'm happy to be here.

Awesome. Well if you don't mind, let's jump right in. Maybe we start off with a quick introduction. What exactly is coexistence?

Sure, so when we refer to coexistence, we're basically talking about a mechanism that allows you to have two co-located radios, so two devices on the same board. And an example of this would be a Bluetooth device and a Wi-Fi device. Operate on the same frequency band, so in this case 2.4 gigahertz, and it allows them to coexist without interfering with each other's packet transmissions. And so basically how this is done is by giving the two devices a dedicated communication interface, so that they can manage their own wireless packet traffic.

Yeah, that makes sense. And I assume you can implement a non-coexistence solution with, say, BLE and Wi-Fi as well. So what are the benefits of using coexistence, and the consequences of not implementing coexistence?

Sure, so having the two devices on the same board without making use of coexistence can sometimes lead to some RF performance issues, which can manifest in things like high packet retry rates, and higher current consumption, and things like that. Or it will cause you to have to increase the size of your board in order to mitigate some of these issues. And so by making use of coexistence, you can not only fix some of the RF performance issues that I mentioned, but it also allows you to tighten the size of your design, even being able to use one shared antenna. And so that can save you on some board space and BOM cost, which is nice.

Oh, wow. Very cool. So it looks like form factor is an area that could truly benefit from coexistence, by being able to bring these two chips closer together. Otherwise they would fight each other. But with a coexistence solution, they can coexist in a peaceful manner. Can you touch on some of the end equipments or use cases that could benefit from coexistence? You mentioned Wi-Fi and Bluetooth being sort of a common pairing.

Yeah, so you can really make use of coex and see it in any application that you would need to have two radios. So one application specifically would be an e-lock that makes use of provisioning. So a lot of times people want to do BLE provisioning, but then be able to access their lock from anywhere, so make use of the Wi-Fi side. And it needs to be small, right? Because it's a door So

Yeah, that makes sense. Because now that you say that, there are several kind of home or building type automation things that I've used personally where I'm provisioning with my phone, possibly over BLE, but then it's Wi-Fi connected. So it seems like those are likely using coexistence, which is pretty cool. And another question for you, is all coexistence the same? Like if I say I have coexistence, do I have it, or are there different types and implementations?

So, good question. There's actually a lot of different kinds of implementations. TI, specifically on our BLE side, we support three different implementations. So that would be 1-wire request, 1-wire grant, and 3-wire. And I could talk about those a little bit.

So for the 1-wire request scenario, the BLE device uses the request signal as an output to the Wi-Fi device, letting it know that it's about to perform some sort of RF activity. So the Wi-Fi can stop whatever it's doing. And so this is a one-way communication from the BLE device to the Wi-Fi device. In the 1-wire grant scenario, it's flip-flopped. So it's a signal from the Wi-Fi device to the BLE device, letting it know when it's allowed to perform RF activity. So again, just one signal but this time from Wi-Fi to BLE. And Lastly, the 3-wire communication or the 3-wire interface uses both the grant and request signals that I previously mentioned. But it also makes use of a third signal that's priority. And this allows the BLE to also relay information regarding priority and what kind of RF activity it's going to perform, so that the Wi-Fi can make a more informed decision.

Oh wow, very cool. So kind of different levels of complexity, depending on the customer use case. You mentioned something earlier that seemed pretty interesting as well. It sounds like form factor is one of the key benefits here of coexistence by bringing these two chips closer together, Bluetooth device and a Wi-Fi device. But you mentioned one additional aspect, where not only can they be placed closer together because of coexistence, but they potentially can also share a single radio design. Is that something you can touch on as well?

Right. So with coexistence, you can really-- it depends on your application. But you can make use of two antennas, or just have a shared single antenna, if you wanted. So you add in an additional RF switch, and then using the coex mechanism it would control which device has control of the antenna at a single time.

OK. Cool, yeah, so it sounds like various options as far as which coex implementation, what hardware options you want, single or dual antenna. And I know in many previous videos, we've talked about TI's BLE and Wi-Fi portfolio. So can you tell us if people want to get started with TI coex, where can they go to get started?

So there is several app notes that we have that talk about how to implement coex. I believe we also have a SimpleLink Academy, and the latest SimpleLink Wi-Fi SDK as well as the latest SimpleLink CC13x2-26x2, SDK both supported. And so you can get started with those two software-wise today. And I believe we'll have those resources linked in the description below.

Perfect, yeah. So it sounds like everything's online. Check the links below. We'll make sure to link everything that you mentioned. And Alexis, thank you very much for coming and educating us. I certainly learned about coex myself, and some of the nuances and benefits to it. So I really appreciate it. All of you guys, thank you for tuning in to another remote session of the Connect series here. As always, we have more great content coming up, more great demos, and more great connectivity topics. Thanks, guys.

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