The auction for the 5G, or fifth generation, spectrum licences in Europe's largest telecoms market is planned for early 2019 and details are being closely-watched to determine whether smaller contenders will have a realistic chance to compete with the established players.
The three existing operators - Deutsche Telekom, Vodafone and Telefonica Deutschland - have pushed back against calls from potential entrants and the German cartel office for auction terms that would lower barriers to entry.
But there are concerns among industry analysts that market concentration has left Europe's largest economy lagging its rivals in the race to build network-dependent connected factories or put self-driving cars on the road.
Germany's antitrust regulator last week called for a fourth mobile operator to enter the market for the 5G auction, rebutting arguments from the "Big Three" that more competition would hit investment.
The proposed terms for the 5G auction, laid out in a document from network agency Bundesnetzagentur (BNetzA), do not include a binding commitment to allow national roaming - which would let a new entrant rent network access where it lacks coverage - a key demand of smaller player United Internet, which is considering bidding.
Without the roaming commitment the incumbent operators can choose whether or not they want to allow the new entrants access to their networks, for example, in rural areas.
The proposed terms, which will be discussed by BNetzA's advisory board on Sept. 24, also foresee that at least 98 percent of German households need to be supplied with a high-speed connection of 100 megabits per second by the end of 2022.
At least 50 megabits per second must be available for busy regional and long-distance railroad traffic lines.
"The coverage obligations may not be not quite as extraordinary as BNetzA describes them but at first sight do impose material capex requirements on the network operators, in our view," Jefferies analysts wrote in a note.
Asked about auction proceeds, BNetzA president Jochen Homann told German paper Handelsblatt that the government was unlikely to generate proceeds in line with those from the UMTS, or 3G, auction in 2000, which amounted to 50 billion euros (44.85 billion pounds).
Deutsche Telekom, late on Thursday, said it expected the BNetzA to refrain from further regulatory interventions into the mobile phone market, adding the proposals were counterproductive.
Vodafone, meantime, criticised requirements to supply federal main roads with 100 megabits per second as "unacceptable", warning of high costs.
(Reporting by Nadine Schimroszik and Markus Wacket. Writing by Christoph Steitz. Editing by Jane Merriman and Kirsten Donovan)