"The notices have been issued to the operators today," an official source said.
The government is likely to get Rs 4,251.83 crore from retrospective charges, and Rs 18,925.82 from prospective charges for excess radiowaves held by mobile operators.
In all, around Rs 23,177 crore is expected from levy of one-time spectrum fee, sources added.
State-owned BSNL will have to pay around Rs 6,912 crore, followed by Bharti Airtel - Rs 5,201 crore, Vodafone - Rs 3,599 crore, MTNL - Rs 3,205 crore, Idea Cellular - Rs 2,113 crore (includes Rs 231.5 crore of Spice), Aircel - Rs 1,365 crore (includes Rs 14 crore of Dishnet), Loop Mobile - Rs 606 crore and Reliance Communications - Rs 173 crore.
Initially, telecom firms were given 4.4 MHz spectrum along with licence for Rs 1,658 crore for pan-India operations and later they were entitled to get another 1.8 MHz on fulfilment of certain subscriber-base criteria.
In November, the government decided that the operators should pay for holding spectrum above 6.2 MHz retrospectively, from July 2008 to January 1, 2013.
After that, for spectrum above 4.4 MHz, they would have to pay for the remaining period of their licences based on auction held last November.
Sources said the Department of Telecom (DoT) has tentatively fixed provisional rate for spectrum in 1800 Mhz band for Delhi, Mumbai, Rajasthan and Karnataka circles where it did not receive any bids, as also for the more efficient 900 MHz band.