Let's now turn our attention to understanding in some detail, what are the basic advantages of millimeter wave because of which it becomes viable for commercial purposes. And the first of which is something we have already discussed in that because millimeter wave are largely unused so far, there are no other services are competing for spectrum in there. And at such, any service that can meaningfully utilize millimeter wave frequency spectrum can have access to large frequency bands and hence larger wide bandwidths and hence less crowding. And as we know by now, higher the bandwidth that is available to a service better will be its throughput capacity and other metrics of performance. And that is a clear advantage in terms of millimeter wave. The other three advantages tend to get a little technical understanding those in detail would require some technical background, but as always, we will try to abstract those details out and try to understand those concepts at a high level nonetheless. So let's try to look at what these bullets are saying. First one is saying more antennas leads to higher gain, why does it seem that millimeter wave can afford more antennas here is where a fundamental principle of radio frequency propagation comes into picture. At a high level, the principle says that the size of the antenna needed to work at a specific frequency is inversely proportional to that frequency, meaning that as your frequency of operation goes higher and higher, the size of the antenna that is needed to optimally send or receive signals and that wireless frequency begins to reduce and reduce. So if you compare two antennas, one is supposed to operate at a lower frequency and the other is supposed to operate at a higher frequency. The one corresponding to the lower frequency would be obviously bigger in size and the one supposed to be operating in higher frequency would be smaller in size. And because millimeter wave spectrum is significantly higher than our traditional frequency bands stands to reason that the antenna size in the millimeter of a bank, typically it tends to be very small as compared to the antenna size in traditional bands like one gigahertz or two gigahertz. So much so that an implementation can vary, but it should be possible for you to find a millimeter wave antenna that is smaller than a typical company. And because your individual antenna size is so small, it stands to reason that within a given physical space, let's say on the Ginobil. You can fit many more millimeter wave antennas as compared to antennas at any lower frequencies like one GHz for example. And that is the reason why this point says here that millimeter wave can utilize more antennas. So I hope that point is clear that why exactly millimeter wave Ginobils can utilize more antennas. The next classes that more antennas somehow lead to higher gates. Let's try to understand that we have previously seen that the fundamental job of an antenna at the transmitter is to transmit a wireless signal. A wireless signal is a form of energy. So indirectly every antenna is transmitting some energy outward. And if you have more antennas, more of them will be transmitting energy. And at such the Ginobili's if you imagine with these more antennas in aggregate will be transmitting more energy as compared to before, when it would have only a limited number of antennas. And because the Ginobil is now able to transmit more energy in technical terms, engineers call it higher gain. Of course, there are a few other connotations of the world again. But in this context and at our simplified level, this is what we need to understand that more antennas allow you to transmit many more wireless signals at a time and hence more wireless energy at a time does, leading to higher game. Next point is about something called high directivity. Now, what is directivity in this parlance? Well, once again, technical explanation tends to get a little hairy and we are in fact going to dedicate some time to understand this precise concept in the 5th module about massive. But let's at least make it an attempt to understand the principle of directivity at a high level. When you have these more antennas on the Ginobil which are typically arranged in a two dimensional rectangular panel, you have two options. You can either let each antenna work as an individual and do its own thing or you have the option to make some or all of those antennas work together in unison as one unit and coordinate the kind and amount of energy that they transmit outwards. And when you execute some smart signal processing algorithms in the back end to make multiple antenna elements work together in unison. What happens is that rather than just translating their energy in any random direction, what they can do is they can coordinate with each other and focus their energy in a certain precise direction of interest. For example, if your user is located in that direction, the genome B antenna panel by coordinating all the individual antennas should be able to focus its energy in this direction. If on the other hand, your user is located in that direction, not a problem, you will change some of the parameters on the genome B antenna panel, the panel will still continue to work in unison and those antenna elements would now send their energy focused in this direction. And because your antenna elements are now able to operate as one unit and focus their energy in the desired direction of interest. Rather than letting it spill over all over the three dimensional space, you can achieve higher spectral efficiency just like if you are able to focus better, if you're studying you'll be able to study more. If you are focused well when you're working, you'll be able to get more work than your efficiency when you have more focus in your personal life is higher and just like that. When antenna elements are able to focus their energy in the desired direction where the user is, for example, that is when the transmission happens to give us higher spectral efficiency. So what I've given you so far is just a high level background. Technical explanation tends to get a little complicated, but we are going to take another crack at it when we have more context in memorial Fire. But as of now keep in mind that when you have multiple antenna elements, the Ginobil has the choice to make some or all of them work together in unison so that those antenna elements coordinate with each other and focus their outward energy precisely where it is needed and avoid wastage in any other direction. That focus ultimately gives you higher spectral efficiency, just like how better focused while studying and working helps you get more work done.
