MUMBAI: Reliance Jio Infocomm could again be at loggerheads with rivals Bharti Airtel , Vodafone India and Idea Cellular , this time over the auction of airwaves in the cost-efficient 700 MHz 4G band , with the Mukesh Ambani-owned company’s nudge to the government to sell the spectrum being opposed by incumbent telecom operators.Jio has been trying to arrive at the best spectrum combination for its upcoming 4G services, the launch of which is likely to be scaled down in December to metro cities, if not delayed altogether to March, said two people familiar with the company’s plans. The company has told officials in the telecom department about its interest in the 700 Mhz band, and has offered to mop up as much as 20 MHz in this band if auctions happened early next year.Incumbent telcos though want a lead time of around two years for the ecosystem to develop before buying it, more so since the airwaves are likely to be steeply priced. They realise that they would have to bid for the airwaves, whenever it is auctioned, which would drain them of further capital at a time they are already investing heavily in expanding 3G and rolling out new 4G networks."Jio has assured the telecom department that it will buy any surplus airwaves in case others don’t bid," one of the people said.This is to set at ease the department’s fears about auctioning a band which won’t find many takers. The department, on its part, has already sought a starting price for the band. An official had earlier told ET that the regulator’s 2012 recommendations offer a pointer to 700 MHz band pricing. It had then pegged the base price of the band at two times the price of airwaves in the 900 MHz band. The latter more than doubled to nearly Rs 7,500 crore a unit in March.Jio didn’t respond to an email seeking comment until press time Wednesday. Rajan Mathews, director general of the Cellular Operators Association of India, said the department shouldn’t be in a hurry to auction 700 Mhz airwaves. The association represents GSM telcos like Airtel , Vodafone and Idea. "We want the DoT to identify and harmonise 700MHz airwaves with a global standard and tell us when it can be put up for auction. It will give the equipment and handset makers a leg up to start also," he said.A senior executive at one of the incumbent companies said it will take around two years for 4G to get widely adopted. "It is only after that 700 MHz will see true bidding competition", and not in the near future, he added.Jio, the moneyed new entrant and a unit of Reliance Industries , is building a fresh spectrum holdings. Airwaves in the 700 Mhz band have already seen some network and handset ecosystem build out in some African and Latin American countries and Australia.China is considering the launch of TDD (4G) technology on 700 MHz, which is synergistic to the standard to be used for the 2300 MHz band. Jio mostly has the 2300 MHz band.As a low-frequency band, the distance covered by airwaves in the 700 MHz band is over two times 1800 MHz and four times 2300 MHz for a similarly powered emitter, thus lowering capital requirements. Moreover, 700 MHz is able to more easily penetrate a concrete wall than higher bands.The battle over 700 Mhz airwaves comes shortly after Jio and the top GSM telcos recently sparred over the move by the latter to raise the cost of liberalising CDMA airwaves and reducing the permissible 10 MHz cap of such spectrum. The fight between the two camps is getting bitter by the day as they prepare to fight for subscribers to their respective data services – on 3G and 4G – which will define their growth in the years to come.