Wireless IoT Challenges In the Super-Connected World (English)

Tyler Kern (00:00): 

Welcome to -CONNECTED World, a podcast for engineers to learn more about the trending topics influencing the connected world and technology turning today's impossible into tomorrow's awesome. 

Tyler Kern (00:15): 

Hello and welcome to CONNECTED World, the podcast from TE Connectivity. I'm Tyler Kern. Thank you so much for joining me for this episode of the podcast. Today, I'm speaking to Christian Koehler. He is the Manager of Product Management for RF solutions at TE Connectivity, and we're going to be discussing wireless IoT challenges in the super connected world. So, Christian, thank you so much for joining me. 

Christian Koehler (00:35): 

Thank you so much. Thank you for the kind invitation. Very much appreciated. 

Tyler Kern (00:39): 

Well, I'm really excited to get your expert analysis and insights on this topic today, Christian. And just to begin, this is a question that we've asked several of our experts on the podcast so far, but what are some of the biggest challenges facing wireless IoT in the connected world right now? 

Christian Koehler (00:53): 

This is really a big thing. I would start with a few global challenges. I would call them global challenges like technical challenges, which belong to coverage. So, IOT wireless, IOT devices. They commonly need to cover a certain area, NFT efficiency for example. The data rates, which are normally required these days, and other technical features in combination with wireless. So those are some of the technical challenges. Then, there are some commercial challenges, which is like quality of service, take quality of service for example. Ultra-reliable, low latency communication. You may have heard about this. And so, it just often requires very short latency, very quick reaction of wireless services. And so, the quality of services is becoming much more important these days for certain applications. Then there's security. think about all the devices which are connected. They have to stay secure, and they should not be hacked at any time, and they should be upgraded for security reasons

Christian Koehler (02:03): 

And so on. Last but not least, cost and scalability are two important parameters in terms of commercial challenges, and the third thing is the ecosystem. So, when thinking about the ecosystem, it is this solution, which is most likely going to be developed, future proof. It set a global reach or inter-operability given on devices when the markets will expand from the local markets to other regions, for example. So, there is enhanced mobile broadband, which is a challenge with the data rates going up to 10 gigabit per second and more. There is massive machine type communication. Massive often means like a million or a couple of million devices in a square kilometer. That is commonly the ultra-reliable, low latency communication. And there are a few wireless standards, which customers and developers can select from, those with short range, that are low power rate, area standards. And there is a traditional cellular standard available. 

Christian Koehler (03:16): 

And depending on your area to cover and on the energy consumption requirements and the data rate requirements, the one or the other one of the standards might be the good one, the right one for this specific application. Now what we also face is the very strong, exponential growth of wireless traffic. That means it tends to get more and more congested. So, there are not so many new frequency bands going to be added to the spectrum. At least any sub six gigahertz spectrum; just a few new frequencies are available to be [free from] interference. So, with exponential growth of traffic, that would be, yeah, interference everywhere, which is kind of a competition in the air or whatever, for the best connectivity. There is also complexity of antenna design. So, what do I mean? Antennas are normally different from regular passive components or from most of the regular passive components. Antennas, they need to… to be taken differently. 

Christian Koehler (04:22): 

There was a tendency to avoid this complexity or even ignore this complexity. There was a tendency to take on antennas as, any of them, as if components like capacitor or resistor or so. And, the next common challenge is the understanding of RF requirements. So, how do I know my antenna is good enough? And how do I know it's good enough today? And even more important, that it’s good enough tomorrow when the exponential growth for the continuous…more interference is being added to the channels? And so on. There is a high level of integration of functionality into IOT devices, which is another challenge. 

Christian Koehler (05:04): 

So, lots of key performance indicators have to compete [for] that. So, the one, the one I have, should have the biggest battery. The other one [we] want to have should have [is] the biggest display, and we want to have the biggest antenna. And there is often a constant fight for the best possible compromise within those devices. That is also power consumption. I think I mentioned that already; the cost performance ratio. Another big challenge we are facing is experience in the market. So, experience of… of startup companies, for example, even well-established companies who did not deal with wireless services in the past. When all, all the sudden there need to be wireless connectivity, integrated to devices. And the level of complexity of it is taken, very often too, I would say a little bit too loose or easy, which can lead into problems.

Tyler Kern (06:00): 

Absolutely, absolutely. So, there are obviously a lot of, a lot of challenges in the market right now, and a lot of challenges for engineers in the industry. And you mentioned several there. Frequency, congestion, and added complexities and things along those lines. So Christian, how are you seeing engineers face these challenges, and what innovations are coming out of these challenges to help solve these problems for the future? 

Christian Koehler (06:23): 

If we look into the…into the industry, I think the most advanced engineering groups can be found in smart phones of handhelds. So wireless Handhelds like tablets or even laptops. So, developing antennas for those devices. There was nothing left to coincidence. Anyone in the loop, based on decades of experience, knows what is important would need to be considered. So, a few people, they really know how to design antennas, and nothing goes wrong. They get to a super good working compromise very quickly, but often, customers have to implement wireless services. They haven't done this before, and just the availability of hundreds and thousands of so-called standard antennas in the market make believe that what is written on the data sheet is kind of true. And what I can say from, from experience, everything is true. Accept RF data. So of course, antennas, 

Christian Koehler (07:34): 

I, as an antenna implementation, cannot just relay on RF database and the data sheet as for any other passive components, like capacitors. What's written on the data sheet is commonly true for antennas. It's also true, but it's related to, let's say a reference ground plan measured in free space and so on. So, it's very dangerous to use data sheets, but very often this is, this approach has been taken. Select an antenna from the catalog, put them on the board, switch on the board, and it's not working. And then sometimes a trouble arrives or to surface problem afterwards. So, antennas, usually we get a lot of requests from IoT opportunities where we need to be small and cheap. We need to be, we need to have the smallest antenna, the cheapest antenna. And am I asking myself, by just small stuff, is “What is cheap?” 

Christian Koehler (08:30): 

And coming back to the phone, goes to the mobile phone guys. Some tried to make antennas as… as big as possible. And so, cost is also super important, but what is the opposite of a cheap antenna when the connectivity isn't that good enough? What we also see often is antennas get[ting] implemented very late in the design cycle of new devices. They finally…so when this occurs they get squeezed in between other components of existing devices, which need to be upgraded by wireless service. So, the understanding of the devices, part of the antenna is very often not so well-developed, and TE can support to tackle those challenges by a holistic approach based on decades of experience with mobile phones, which to me, I would call this noising challenging devices. They are commonly small; they have to fulfill strong customized requirements. They commonly have to be battery-efficient. They commonly have a big battery, a big display, and so on. So, everything has something contradictory to it-- a function of antennas--, and still up to six or seven or eight antennas normally have to break into such small form factors. So, this is where the TE team can really support. We see the approaches taken by others are very often not tuned and tailored to the specific cell antennas. 

Tyler Kern (09:58): 

Christian. One of the things that you mentioned was, when in the design cycle and antenna and implementation was considered, that normally it's coming too late in the process. They're being squeezed between other components. From your perspective, what is a good time during the design cycle to consider where the antenna should go, and the implementation of the antennas within the device? 

Christian Koehler (10:18): 

This is a very good question. And there are a few clear statements from guys like AT&T. I would say in my opinion that there are three key elements or a design cycle, we have for a new development of a device. First, the definition of a use case, to [have] clear understanding of RF requirements, for example, an HD security camera that requires an omni-directional panel, it normally requires a strong signal. So, a good kind of activity, maybe two or three antennas to run MIMO for, for a good throughput waste and energy monitor, which commonly has to transmit a few bytes or kilobytes per day. And its battery driven, [and it] has totally different requirements, and so the antenna need[s] to be very, very efficient. So, second, the second key element to me is preparing a link budget to understand worst case conditions in the field. Even if the device is working in the lab, that doesn't mandatorily mean it's…it's working very well in the field and rural areas where the signal is fading. 

Christian Koehler (11:26): 

And the question is, do we have enough margin to guarantee required performance? And the third key element is the consideration and understanding of the device conditions. What stays size of device do I want to make? What components, what other antennas, what shooting cans, what batteries, your transformers also would have to be near antennas, which can have an impact. So those three elements are normally what should describe the level of complexity, which is involved in antenna design, and this is making clear [that an] antenna commonly cannot be designed at the end of the design cycle. Right. [Considered right at the beginning of a product, or even of furthermore [sic]. Normally, even if we think about antenna design right at the beginning of a product cycle, in mechanical change of a device, [the design] must be verified related to a potential influence on the antenna performance, which may require rapid tuning adjustments [that is] on time, when required. 

Christian Koehler (12:30): 

I would like to talk about the next sample from a power meter. We came in early and there was a requirement to get an LTE antenna on a power meter for remote control for remote monitoring and everything was perfect. So, the peer support was precise. Ground plane was precise. The antenna was in a perfect place. And during the design, a super cap had to move a few millimeters to see antenna, which was killing the low band performance completely. So, it took us awhile to find the root cause. It's such minor changes in the design of the device [that] can have a very, very significant impact. So again, I'm pretty sure we should talk as…as early as possible in the design cycle about antenna implementation. 

Tyler Kern (13:23): 

You know, Christian we've…we've talked a little bit about how antenna performance is affected by its placement. And you had a great example there of just an example where the antenna’s low band performance was degraded based on components that were placed in nearby it and things along those lines. So, tell me a little bit more about performance indicators for embedded antennas. How is antenna performance measured and what does that look like? 

Christian Koehler (13:49): 

If you think about a successful…design of an integrated or embedded antenna. I would not like to talk so much about external antennas, because they are rather easy to implement and… and measurements and performance indicators are rather predictable and repeatable. Not so on embedded antennas. So, for design of embedded on antennas into wireless device, a number of measurements must often be made to quantify the antenna performance in the actual product. So, it has no use to measure the antenna in free space, and then implement into the device and leave performing similar. So, there were a few performance indicators like bandwidth. So, bandwidth is very, very important, which has to do with antenna design, with antenna location. Another indicator is gain of course, and finally, some, some people, or even a lot of people that look for high gain, except for antennas, which are supposed to be a directive for point-to-point connections, or so the antenna should rather be little like zero or two dBi. 

Christian Koehler (14:56): 

So, very little gain means very, very good omni-directional performance, and a lot of IOT devices, they have to perform in a random environment, so nobody can predict upfront. Whereas my gateway…whereas my access point with relation to the IOT device--.so, it can be in front of, can be on the backside, can be to the right, to the left... So, the IOT device performs with an omni-directional, perfect. If There is a stand with gain, control and isolation, I should not forget isolation in some of the devices. There are multiple antennas needed. They often should not influence each other or interfere into each other. The very, very important simple thing is often efficiency. Sorry, the efficiency of my voice just dropped a little bit and you might have seen or heard what happens. So, even if my bandwidth is fully okay, my gain is okay, the isolation is okay, but if the efficiency is not good, it's very hard to understand. 

Christian Koehler (16:02): 

So even if there was, if there was a lot of interference, I need to compete with this interference and get through and speak loud enough. So, efficiency, we have seen efficiency to be one of the single most important parameters to be measured for embedded antennas, which can have kind of peak rated efficiency tutor, whatever happens, tight integration, other potential potentially impacting components near. So, the antenna needs to act as a transducer between radio and propagation medium. And if there was an impact to the antenna, it won't, it won't speak. 

Christian Koehler (16:41): 

I want to explain this on, what is this, a worst-case scenario? We had a customer that had the antenna perfectly tuned. The bandwidth was [with] super good isolation. So, antennas did not interfere with each other. And it wasn't antenna for printer. So finally, on the outside of the printer, there was a paint with metal content. So, with painting, you print a housing with metal containing a varnish. The customer created kind of a Faraday cage. All the parameters were perfect on the antenna, everything nicely tuned, but the efficiency was zero and the printer did not work as expected. And all the other parameters became of minor importance at this time with a very simple, single impact of a Faraday cage. 

Tyler Kern (17:29): 

That's really interesting. And I, I appreciate the object lesson, the example of what it sounds like when certain aspects aren't working, either interference or, with your voice being muffled and hard to hear. I thought that that was, I thought that was a really great way to describe it, especially on a podcast, which is a listening medium anyway. So, I thought that was really good. So, one of the things you talked a lot about efficiency, what is the difference between VSWR and efficiency? 

Christian Koehler (17:54): 

I am glad you ask this question because VSWR This voltage standing [wave] ratio is kind of a measure of the impedance matching of loads to a characteristic impedance of a transmission line also. So, in other words, the radio, mind you, or the RF module as an impedance of 50 ohms, and within the frequency, the antenna should also perform with a 50-ohm impedance. Then the best VSWR, the voltage standing wave ratio, would be close to one, which is the ideal case. If that would be a shortcut instead of an antenna, this one would be infinite. That would be the best case. On the other side, it's to measure up to tune the antenna, it's enough to have a network analyzer, so you can see how well the antenna is fueled. It does tell much about the antenna performance. It's telling it's good, matched together with a bent with measurement. 

Christian Koehler (18:53): 

You have got a very good basis set of information for the antenna characteristic. However, within a device with all the trusses closed and all the components inside, and ideally even switched on to have other sources of noise, like interfaces interfering with the antenna, then the efficiency measurement is a totally different thing. Antenna efficiency is based on comparing to total radiation. How long to the input power to the internet terminals in an easy world? So, if an antenna has an efficiency of 10%, then 90% of the RF power, which is transmitted from the RF module, is converted into heat or something else, but not radiated into air. And so, 10% radiated, 90% transformed into heat. We don't want to make it often, right? We want to make an antenna. So now the question is how to, how to make this better, how to find out what my efficiency is that is required to have an anechoic chamber or better a set Timo chamber, which is an anechoic chamber with a ring of census. 

Christian Koehler (20:04): 

There was a tone table measured, needed to measure the three-dimensional radiation pattern, that takes some time. And then, it's kind of an integration of the power by the radiation. It is just a three-dimension[al] radiation pattern that is providing the efficiency. When this equipment is not existing in network. Analyzer is, is good to check the basics of an antenna, but it's not telling anything about what my efficiency is. So how much, how good is the transmission and the reception of the end device. 

Christian Koehler (20:37): 

So, so for those kinds of parameters, there was a, an aquatic chamber needed. And both they use this for, and efficiency, by the way, they need to be matched up with an antenna fully installed in the device with all components installed. And so, what happens if the efficiency is zero? You can imagine there was no wireless connectivity; customer [is] not satisfied. And if the efficiency is good enough for the lab and not good enough for the worst-case scenario, the same may happen:  unsatisfied customer. So, efficiency measurement is giving a good indication of what performance, what wireless performance I can expect in them in a field.  

Tyler Kern (21:23): 

Excellent. Well, Christian, we're, we're, we're coming to the end of our conversation here today, but I want to give you the opportunity to, to close with anything that we may not have discussed so far about, about antennas and IOT that, that maybe you wanted to mention before we finish up, or even just the summary statement just on the state of the industry. So, if there's anything we haven't discussed yet, or you want to kind of give a closing statement, feel free, let me turn it over to you. 

Christian Koehler (21:48): 

One issue that's coming up frequently is narrow band, the famous narrow band IOT service, often providing safe, safe service, and, and a registered service and licensed spend bands with liability. So sometimes that was kind of a misunderstanding narrow band. I need narrow band antenna that narrow band IOT breaks in the regular, within the irregular LTE bends. And even if the service itself, narrow band is running with kind of a 200-kilowatt bandwidth, does not mean it's a narrow band antenna. So, the antenna for narrow band IOT is basically an LTE antenna and LTE antenna implementation which commonly requires right band antennas like 670 megawatts to 2.2 or 2.7 gigahertz or very light band. 

Christian Koehler (22:43): 

It commonly requires a lot of experience, a lot of competence to get them integrated very well. And this is just one point I would like to, to mention, so narrowband IOT sounds easy, maybe it's easy, but the antenna implementation often requires a much more careful approach compared to a single band antennas or Viola services like LoRa which is 868, 915 MHz or 6 for your Bluetooth, 2.4 GHz or Wi-Fi or so, so this is all relatively easy compared to implementing a narrow band IOT cellular antenna, as a closing, I would say the antenna is a very important connector. 

Christian Koehler (23:27): 

We are connected company, right? And for me, antenna is the most important connector of wireless devices. It's a critical component, and it's good to have partners with not just the equipment available, but also the competence to integrate antennas and tune them basically do successful integration of an embedded antenna into wireless devices. Depends on the understanding that the entire part of the device is, is part of the antenna. Very likely. This is the case. So, in my opinion the antenna cannot be added at the end of the design cycle. It must be designed from the very beginning and what we sometimes realize I'm fixing antenna problems in the certification lab it's, time-consuming, it's very expensive. 

Christian Koehler (24:11): 

And so, this is where TE connectivity is well-known for--its professional approach to generate high performance, embedded, and external antenna solutions. I would call an antenna most likely antenna solution, rather than just the component. And this is addressing the needs of the exponentially growing wireless traffic, and TE engineers have been developing antenna solutions for some of the most challenging applications during the last 20 years, I would say. And, we would be very happy to partner with our customers and make an antenna development very easy and simple, even if it is super complex. Happy wireless! 

Tyler Kern (24:54): 

Excellent. Well, Christian Koehler, Manager of Product Management for RF Solutions at TE Connectivity. Christian, thank you so much for joining me today and diving into the challenges in the super connected world for wireless IOT and talking about antennas and so much more Christian. We are, we really appreciate your time today. 

Christian Koehler (25:11): 

It has been a great pleasure, Tyler. Thank you very much. 

Tyler Kern (25:15): 

Thank you. Thank you very much. And thank you to all of our listeners out there for joining us for this episode of the show. We appreciate it very much. Of course, we have previous episodes. You can go back and listen to as well as future episodes. So, make sure you're subscribed there on Apple podcasts or Spotify, and we'll be back soon with those new episodes, but until then, I've been your host today. Tyler Kern. Thanks for listening.