It is not always easy to illustrate the speed differences between 5G using low-band spectrum and 5G using mid-band spectrum, to say nothing of millimeter wave 5G. T-Mobile’s early experience shows an order of magnitude (10 times) difference between mid-band and low-band end user speeds.
The mid-band advantage comes in many ways, including wider channels, more physical spectrum and higher frequencies. All contribute to the higher bandwidth capabilities and faster speeds.
Channel bonding, spectrum aggregation, smaller cells as well as better radios and modulation techniques also help. But higher-frequency spectrum, all other things being equal, accounts for most of the improvement.
As a simple example, assume that every zero crossing of any wave represents the opportunity to code a bit (one or zero). Using a very simple coding, the total amount of bits that can be represented in one second of time hinges on the number of oscillations a wave makes over that period of time.
Higher-frequency signals make more crossings, and therefore can represent more symbols. And that is why millimeter wave signals have such high bandwidth: there are simply so many more zero crossings in any unit of time, compared to lower-frequency signals (600 MHz to 800 MHz or 2-GHz, for example).
Over time, all the above improvements have helped boost available bandwidth and end-user-experienced speed.
The simple rule is that more bandwidth means more capacity, which means higher data rates are possible. But bandwidth is based on channel width, signal-to-noise ratio and signal frequency. It is that latter difference that drives much of the order-of-magnitude increase in speed on a 5G network, comparing low-band frequencies to mid-band signals.
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