maximizing the use of spectrum. By using OFDM format and bit loading, the researchers achieved a 938 Gbps transmission data rate with less than a 300 MHz gap between different RF and mm-wave bands." ...

The frequencies used in OFDM system are orthogonal. Neighboring frequencies with overlapping spectrum can therefore be used. This property is shown in the figure where f1, f2 and f3 orthogonal. This ...