The Federal Institute of Telecommunications (IFT) said it aimed to auction 60 Megahertz (MHz) of spectrum in frequency bands between 1.71 Gigahertz (GHz) and 2.17 GHz.
It did not specify when the auction would take place next year.
Mexico's government completed a major telecommunications reform in 2014 designed to loosen the hold Slim's America Movil has long had on the market. Next year could see the arrival of US giant AT&T to compete with the billionaire.
At the weekend, the IFT approved AT&T's $1.7 billion purchase of Iusacell, Mexico's third-biggest mobile operator, which lags far behind America Movil.
Slim's company has around 70 percent of the mobile market in Mexico.
The IFT said it would also auction 10 MHz of spectrum between 440 and 450 MHz to boost available capacity for private radio communication systems, as well as blocks of frequency for social and rural use between 824 and 894 MHz.