Hopping can lower many kinds of interferences, such as co-channel interference, adjacent channel interference, inter modulation interference, etc.
Hopping turns the consecutive long time interference of mobile station into discontinuous interference of single burst, and such interference can be greatly lowered through channel decoding, de-interleave and error correction technology. After hopping technology is adopted, GSM BTS and mobile station can work in harsh radio wave environment.
In a word, hopping makes cell planning more flexible. The effect of interference equalization depends on the hopping mode. The best performance can be achieved if interference signal and useful signal use different hopping sequences (e.g. irrelevant sequence). The less the relativity, the better the equalization effect.
If both interference signal and useful signal use the cycle hopping with the same hopping sequence, they may remain on the same frequency with consistent pace, and the interference on useful signal will be no hopping is used. This is the same as the case in that two hopping sequences are totally relative. Therefore, the interference diversity effect of random hopping will be better.
In a full load system, all interference signals are transmitted at the same time, resulting in a continuous interference. Even so, random hopping sequence still can improve communication quality. However co-channel cells must use different hopping sequences. The more frequencies involved in hopping, the better the performance.
In Short Advantages of Hopping:
- Get an agreeable radio environment.
- Provide a similar communication quality for every user.
- Tighter reuse patterns are possible to be used for larger capacity.