Attenuation Characteristics

Can Some one please tell me , what is the effect on attenuation when we use high frequency and when we use low frequencies. Please also tell that in GSM transmissions which one (high freq or low freq) is better.. and Why? Or you can tell if we use low freq for transmission in GSM why we do that and if we use high freq for transmission in GSM why we do that ?
Please Help ...thanks

The attenuation vs frequency (or distance) is coming from the Free Space Path Loss formula:

Free Space Path Loss(dB) = 27.6(dB) ? 20*LOG[Frequency(MHz)] ? 20*LOG[Distance(m)]

So, making double the frequency or double the distance the Path Loss (attenuation in dB) will increase with 6dB.

well the above message says it all...