Radio spectrum

[EngIntoHW]

I read about LTE and read that:

In terms of actual figures, targets for LTE included download rates of 100Mbps, and upload rates of 50Mbps for every 20MHz of spectrum.

I wonder, how can 100Mbps and 50Mbps rated signals can occupy just 20MHz of spectrum.
Are they being compressed before sent over spectrum?

 

[RCinFLA]

Multi-level modulation

LTE uses up to 64QAM.

 

[EngIntoHW]

Thanks RCinFLA!