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Currently in the U.S. certain companies are granted leases on certain frequencies for cell phone communication. I was discussing with a friend how this allows a company with a lower frequency to get a physical advantage over another cell service company that may only have the option to lease a higher frequency. (For building penetration and distance of transmission)

Ignoring the engineering problem of revamping their systems, are there any physical limitation to opening up the leases and allowing all the major carriers to operate on the same band/frequency?

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2 Answers 2

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If two adjacent cells share the same frequency, they will interfere with each other.

Generally, frequencies are reused in non-adjacent cells, to give a chance for the distance to attenuate the unwanted signals to a manageable level of interference.

With proper design of signals (OFDM, with cyclic prefixes to mitigate multipath), you can achieve an SFN, Single Frequency Network.

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  • \$\begingroup\$ Hmm I guess I understand, but I imagine some common standard like we have with WiFi would be capable of handling this? Or would there just be too much interference and nothing could get through? \$\endgroup\$
    – SupaJord
    May 24, 2019 at 15:21
  • \$\begingroup\$ @SupaJord There is no design standard that can mitigate just the simple energy of an unwanted transmission ending up in the bandwidth of your wanted transmission and trashing it. The standard way is that if cells are adjacent, then frequencies are not reused. If frequencies are reused, then cells are not adjacent. The OFDM case works only by broadcasting the exact same modulation on all transmitters. The interference you get by being different distances from transmitters is just several different timed receptions of the same data, looks like multipath, which cyclic prefix handles. \$\endgroup\$
    – Neil_UK
    May 24, 2019 at 15:29
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I've realized the intense wish (among RF students in recent years, even the last decade) to explore MIMO ---- multiple-input-multiple-output ---- antennas, is the local generation of

phased-array systems

for communication at the local/router/cellsite/home communication-links.

With the tracking of where each subscriber in the service area of a cellsite, with the plenteous compute power to craft each RF emission at each of the numerous antennas atop those cell-towers [by manipulating the I+Q energy of EACH CHANNEL], the cellsite can beam energy at each handset.

The cellsite can beam energy at each handset.

Additionally, reversing the behavior, the cellsite can compute how to peak the synthesized-rf-antenna-pattern response to each handset, even as the handset moves, and the cellsite can direct nulling-responses at co-channel interferers of other cellsites.

IMHO

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