How 4G LTE Tower Bandwidth Affects Wireless Internet Speeds

The speed of your fixed wireless internet connection depends in part on the bandwidth of your cell tower. 4G LTE towers have one of six potential bandwidths – 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz – which provide different network capacities. When the tower is below capacity, internet speeds are fastest. When it’s over capacity, speeds slow down to make room for everyone on the network.

Carriers Have Access to Limited Radio Spectrum

Mobile internet transmits online data between your device and the nearest cell tower using radio waves. The speed and signal range of these transmissions depends on the radio frequency of the connection. Low radio frequencies are slower, but transmit online data further. High radio frequencies are faster, but don’t transmit online data as far as lower frequencies.

In the US, most 4G LTE towers use the 600 MHz, 800 MHz, 900 MHz, or 1900 MHz cellular frequency bands. The FCC divides the country’s radio spectrum (from 30 Hz to 300 GHz) into frequency bands, which it licenses to specific cellular carriers in different parts of the US. Each carrier has exclusive rights to their frequency bands in their region – which cuts down on radio interference between overlapping networks.

If your tower uses a higher frequency cellular band like 900 MHz or 1900 MHz, your potential internet speeds will be higher, but your coverage will be more limited. If your tower uses a lower band like 600 MHz or 800 MHz, you’ll have slower potential speeds, but better coverage. To find out which band your tower uses, see this full list of which carriers use which frequency bands or find out more about the nearest tower on cellmapper.net.

Towers with More Bandwidth Support More Users

Every 4G LTE tower uses a specific amount of space or “bandwidth block” of radio spectrum within its frequency band: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz. While a 20 MHz bandwidth block provides the highest capacity, carriers give some towers smaller blocks because radio spectrum is limited and, sometimes, a smaller block provides enough capacity.

Here’s how many connected devices – such as wireless routers, phones, or tablets – your tower can support at full speed at one time, depending on its bandwidth block:

Cell tower bandwidth block Devices supported at full speed
1.4 MHz 60
3 MHz 120
5 MHz 200
10 MHz 400
15 MHz 600
20 MHz 800

Bigger Bandwidth Blocks Mean Faster 4G LTE Speeds

When more devices connect to a tower than it can support at full speed at one time, it begins to ration speeds to provide internet access to more devices. A sudden drop in your fixed wireless internet speeds could indicate that your tower is currently operating over its network capacity. Also, if you’re consistently seeing 4G LTE speeds of less than 20 Mbps download and 5 Mbps upload, the nearest tower could continuously be operating over its network capacity.

Carriers can take several different steps to boost internet speeds on congested towers. They can artificially increase the tower’s speeds by improving their protocols and equipment or they can add more bandwidth to the tower. The second approach can be extremely effective at increasing speeds. For example, T-Mobile doubled its 600 MHz 4G LTE speeds when it doubled the bandwidth blocks of its 600 MHz towers.

Stephen Kota

About Stephen Kota

Founder & Primary Author

Stephen enjoys photography, boating and gardening. He cares for pet Kois in his water garden.

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