Existing 4G Spectrum

I suspect that most people don’t realize the small number of frequencies that are used today to support cellular service. Below is a list of the frequencies used by each US cellular carrier for providing 4G LTE. Except for Sprint, they all use the same basic frequencies.

Frequencies (in MHz)

AT&T  – 1900, 1700 abcde, 700 bc

Verizon – 1900, 1700 f, 700 c

T-Mobile – 1900, 1700 def, 700 a, 600

Sprint – 1900 g, 850, 2500

The letters represent separate licenses for specific sub-bands of the various frequencies. For example, the 1700 MHz band has been licensed in bands a through f and the carriers own rights to various sub-bands rather than to the whole spectrum. The same is also true for 1900 MHz and 700 MHz spectrum. In many cases, the licenses for the various spectrum bands are not nationwide. This means the frequencies used in Cleveland by one of the carriers might be slightly different than the spectrum used in San Francisco.

The carriers are using these limited spectrum bands today to support both 4G voice and data. In metropolitan areas, the carriers are in big trouble. They are finding it impossible to satisfy customer requests for data service, which is resulting in customer blockages or greatly reduced broadband speeds.

One of the primary reasons that the carriers are running into blockages on 4G data is that they aren’t deploying enough different bands of spectrum for broadband. The carriers have three remedies that can be used to improve cellular data – use more bands of spectrum, build more cell sites (small cells), and implement 5G which will allow for more simultaneous connections.

The CTIA, the lobbying group for the wireless carriers has been heavily lobbying the FCC to allocate 400 MHz of additional mid-range spectrum for cellular data. The FCC is considering repositioning numerous bands of spectrum and the CTIA wants to grab everything possible for data purposes.

Unfortunately, spectrum alone is not going to provide the solution the wireless carriers are hoping for. One of the primary reasons that the cellular carriers only use a few different bands of spectrum today is to simplify handsets. There is a huge price to pay for using multiple bands of spectrum in a cell phone. The more bands of spectrum, the more antennas that must be supported and the more power that is used.

If the cellular companies try to load many more bands of mid-range spectrum onto cellphones they will have majorly overstressed the battery life of phones. Most cellphone customers are not likely going to want to trade faster data speeds for shorter battery lives. As I look forward at the strategies of the cellular carriers, the battery life of cellphones might be their biggest limitation. The question is not so much about how much data a cellphone can handle, but rather how much battery life must be sacrificed to gain broadband  performance. The only solution for this is likely some new battery technology that is not yet on the horizon.

I don’t believe that the average cellphone user values cellular data speeds in the same way that they value fast landline data speeds. 4G today is easily capable of streaming video and there’s no reason on a cellphone to stream more than one video stream at the same time. 4G is reasonably okay today at operating most celular apps. The one group of cellphone users that always want more bandwidth are gamers – but there is no way that cellphones are ever going to be able to match the capabilities of gaming systems or gaming computers using landline broadband connections.

I scratch my head every time I hear 5G claims about providing gigabit cellular service. I don’t want to sound like an old-timer who sees no need for greater speeds. But I think we need to be realistic and ask if superfast cellular bandwidth is really needed today – after all, there are still no landline applications for homes that require anything near to a gigabit of bandwidth. The primary reason homes need faster download speeds is to handle multiple big bandwidth applications at the same time, something that is not today a requirement for cellphones.

The idea of gigabit cellular is mostly coming from the imagination of the cellular company marketers. The 5G standard calls for eventual ubiquitous 100 Mbps cellular speeds. Even achieving that much speed is going to require tying together multiple mid-range bands of spectrum. I’m having a hard time seeing the additional revenue streams that will pay for the massive upgrades needed to reach the 100 Mbps goal. The cellular companies all know this but aren’t talking about it because that would dilute the message that 5G will transform the world.

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