The lower frequency wireless spectrum is made up of low- and midband frequencies. Low-band frequencies operate at around 600 to 700 megahertz (MHz), while midband frequencies operate at around 2.5 to 3.5 GHz. This is compared to high-band MM wave signals, which operate at approximately 24 to 39 GHz.
MM wave signals can be easily blocked by objects such as trees, walls and buildings -- meaning that, much of the time, MM waves can only cover about a city block within direct line of sight of a cell site or node. Different approaches have been tackled regarding how to get around this issue. A brute-force approach involves using multiple nodes around each block of a populated area so that a 5G-enabled device can use an air interface -- switching from node to node while maintaining MM wave speeds.
Another approach -- the more feasible one -- for creating a national 5G network is to use a combination of high-, medium- and low-band frequencies. MM wave may be used in densely populated areas, while low- and midband nodes may be used in less dense areas. The low-band frequencies can travel longer and through different objects. One low-band 5G node can stay connected to a 5G-enabled device for up to hundreds of square miles. This means that an implementation of all three bands will give blanketed coverage while providing the fastest speeds in the most highly trafficked areas.
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