NEW DELHI: The Department of Telecom may go slow for auction of spectrum next year if operators do not invest in infrastructure to make optimum use of available airwaves and improve quality of services, sources said. According to official sources, the DoT is of the view that despite auctioning the largest amount of spectrum earlier this year, operators are not investing in infrastructure, as required, which is leading to call drop problem. The DoT had planned to conduct the auction early next year but is now reconsidering on the timeframe. A top DoT official said, “For better utilisation of spectrum, operators need to adequately invest in the existing airwaves first and after that additional spectrum will be made available for auction.” The DoT has already written to sectoral regulator TRAI for seeking reserve price of various bands including 700, 800, 900, 1800, 2100 and 2300 MHz that can be used for 2G, 3G and 4G services. The government expects a revenue Rs 42,865.62 crore from communication services in FY 2016, which include proceeds from spectrum auction and other charges levied by the DoT. Telecom Regulatory Authority of India (TRAI) Chairman RS Sharma told PTI that the recommendations for base price of all these bands will be out soon though he did not divulge the exact timeframe. An audit by DoT recently found out lack of investment in infrastructure along with operators putting more equipment for 4G services than for 2G or GSM as the main reasons for call drops. While coming out with a consultation paper on call drops yesterday, TRAI also said lack of investment by operators in infrastructure may be one of the reasons for call drops and the investment has not kept pace with the rise in usage. The regulator said investment made in the network infrastructure (other than radio spectrum) in wireless access service segment rose by 4.6 per cent from Rs 2,02,366 crore in 2012-13 to Rs 2,11,691 crore in 2013-14. During this period, the minutes of usage grew by 6.8 per cent. “Clearly, investment has not kept pace with the usage. Thus, prima facie, it appears that lack of investment in network infrastructure by the wireless access providers may be one of the main reasons for the problem of call drops,” TRAI said. Prime Minister Narendra Modi had also voiced serious concern over the menace of call drops and asked officials concerned to take urgent steps to address it as it affects the common people.