Newcomer Reliance Jio, however, said the auction schedule may be drawn up at the discretion of the regulator and the government, but that long-term visibility is imperative for advanced planning to be undertaken by telcos.
Jio said the telecom department should provide a forward-looking timeframe for availability of spectrum for the next 10 years across multiple bands.
The Mukesh Ambani company has also strongly argued in favour of doing away with the 50 per cent in-band spectrum cap, saying it has lost relevance as auctioned spectrum is now technology neutral.
In its written submission to the Telecom Regulatory Authority of India (Trai) consultation paper on spectrum auction, Bharti Airtel has said an "opportune" time for holding the sale of airwaves would be the end of 2018-19.
More From This Section
The consultation process on auction and pricing of spectrum should be initiated between September to December 2018, when operators are better placed to assess their future needs, it added.
"We believe, if auction is conducted in the near future, then it would not result in realisation of full value of proposed spectrum put to auction," Airtel has said.
Flagging the industry's "extreme financial stress", Idea has lamented that operators, as it is, are finding it difficult to fund even existing spectrum payments and the "business case made out earlier for the spectrum won in previous auctions has already failed".
India's largest telecom operator Airtel has said the Spectrum Usage Charges (SUC) have added substantial financial burden on the industry reeling under Rs 4.5 lakh crore of debt.
Noting that there had been no takers for the 700 MHz band in the 2016 auctions given its "abnormally high" reserve price, Airtel further said value of this band should be kept equal or lower than the price of 800 MHz band spectrum this time around.
It has also recommended that the present intra-band spectrum caps of 50 per cent should be maintained and also extended to new bands on the block like 3300-3400 MHz and 3400-3600 MHz.
Notably, Trai in a separate exercise is also reviewing the existing spectrum caps - 50 per cent within a spectrum band and 25 per cent overall across all bands - applicable on telcos.
Vodafone, which is in the process of merging its India operations with Idea Cellular, has emphasised that timing of auctions should take into account the financial situation of the industry and the ongoing consolidation, but stopped short of specifying a timeframe for sale of airwaves.
Both Airtel and Vodafone have said that Trai should not immediately prescribe any rollout obligations for 3300-3400 MHz and 3400-3600 MHz -- bands that are being put on the block for the first time for mobile services and where the standards, network and device ecosystem are still evolving.