I think at the beginning of this chapter you mentioned there are different type of spectrum for 5G. From the operator side, do they have any preference on which one to use and why? Operators often do have some preferences as to what kind of spectrum they use and it's not a black and white decision as with any other engineering problem, it's a trade off of multiple factors. So it's a spectrum of reasons, pun intended here. At one end, if you consider low frequencies, we have already seen that lower the frequency, given everything else equal, better the wireless propagation and broader your network coverage. So one might think that operators will always prefer lower frequencies as opposed to higher frequencies. That is not the case however. Because as we have also seen, lower frequencies inherently are crowded because many technologies and many operators want to use those lower frequencies because they are so popular, so in demand, the individual spectrum you get in lower bands often tends to be limited. So there are limitations on what you can do with such a small spectrum. You cannot always hope to get one gbps or 10 gbps of throughput or data speed with such a small channel bandwidth, which is the fundamental limitation of operating in lower frequencies. At the other end of that spectrum of decisions, we know that higher frequencies will have poorer coverage, meaning that you might have those coverage holes we talked about if you don't take any other steps. But the bright side of it is that because higher frequency bands are not so much used by any technology, you tend to have a much wider bandwidth in higher frequency bands as compared to lower frequency bands. So if you're focus is on deploying certain flagship 5G features, you would possibly want to go slightly higher in the frequency domain as opposed to going lower. So that is the principle factor. But beyond that, there are other factors as well. The most important of which is availability, which I also mentioned earlier. Spectrum has to be available for you to be able to use it. Another factor that is very crucial in the initial stages of any technological advancement is whether the hardware that you want to deploy your network based on is the one available from your vendors. Because different frequencies have different considerations with respect to their radio propagation. Hardware for all frequencies is not always available at the same time. So that is another variable that often feeds into the network operators calculus about what frequencies they are going to deploy first and what frequencies are going to be de-prioritized. So these are some of the fundamental factors that network operators need to keep in mind before they decide what frequency they are going to deploy in. I see. If there are so many different options and now just got me worried a little bit if I'm upgrading my phone to 5G phones, do I need to know if I'm using one network operator, which phone should I buy or maybe vice versa. If I have this phone, which network should I go to? Do you mean to say if you upgrade or did you mean to really say when you upgrade? When I'm upgrading. That sounds better. Good catch. So when you upgrade your phone to 5G, and by the way, I have heard this question as well from people before. It actually reminds me of the 3G deployments in old days where at least in some of the developing countries, like I'm from India and I remember that you would have to buy your handset based on what kind of network your operator had deployed. If your operator had a CDMA network, so to speak, you would have to buy a CDMA phone. If your operator had a UMTS network, you would have to buy a UMTS phone. So there was a walled garden, so to speak, between the two technologies. So that reminds me of that little historical precedent. But in modern technologies, that is not the case anymore in that different factors about what frequency bands the technology operates in are largely abstracted out from the end-user. You, as the purchaser of the phone, does not need to know anymore what kind of frequency considerations your network operator is storing with mainly for two reasons. First reason is that if there is a significant difference between 5G's operating frequencies in different geographical markets, our phones are also commercialized, keeping exactly that in mind. So if a certain geographical region has prevalence of certain 5G bands, the phones commercialized and marketed in that geographical region will definitely take care of that factor without you having to know about it. If you know about it well and good, but you don't have to. But from the technological standpoint, the more promising step that the industry has taken on this regard is that off what is known as multi-mode chipsets or multi-band modems. Equivalently, that is to say that the modem that exists inside your phone isn't dependent on just one or two bands anymore. It can support a variety of technologies, like 4G, Bluetooth, Wi-Fi, and 5G. Not only can it support a variety of technologies, in a given technology, it can support a variety of frequency bands. To give you one example, so Qualcomm has Snapdragon modems and those Snapdragon modems are capable of supporting both Sub-6 and Millimeter wave in the same chip set. So if you take that Snapdragon enabled phone to, let's say, North American country where Millimeter wave happens to be more prevalent, your phone will seamlessly work. On the other hand, if you take it to, let's say China or Europe, where Sub-6 happens to be more prevalent, at least as of now, your phone will continue to seamlessly work without you, the end-user, having to worry about whether my phone with work in the new region that I'm visiting simply because it operates on a different frequency than my home market. So short answer to your question is no, you don't have to worry about it anymore.