What is the difference performance wise in GSM frequency bands?

Question

What is the difference for user in terms of coverage/reception in different frequency bands? i.e. does GSM 1800 have better coverage than GSM 900? Why does a lower frequency band show better penetration power? We studied that a baseband signal is modulated to have "higher" frequency to gain distance. Aren't these statements contradictory? Does GSM 1800 cover less area but with better voice quality? Please help!

Answer 1

E = hf; where h is Plank's constant and f is the frequency of an EM wave. Your higher freq GSM will have more energy. But it will be more direct line; that is, it will bend less than the lower freq. [NB: Although lower freq. bends and follows the Earth's curvature better, the difference between 900 and 1800 is so small, there is very little difference in the pathways for either frequency. That is, both are pretty much straightline paths.]

So in the sense you have direct, straightline connection, your higher GSM freq. will have better signal to noise ratio (S/N), which is a measure of clarity of reception. It has better S/N because of the higher modulated energy (the signal) and because static (the noise) tends to exist in the lower frequencies.

One answer indicated no penetration for EM waves. That is, of course, incorrect. But lower frequencies do penetrate better than higher frequencies.

This follows from the inherent EM frequencies of the atoms making up material. They are generally very high frequencies and, therefore, they tend to interfer more with high frequencies than low frequencies. I think most of us have experienced dropped calls or no signal at all inside a building. But step outside and, voila, back in business.

Answer 2

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