Anil Ambani-led Reliance Communications today paid Rs 1,651 crore to the department of telecom (DoT) as fee for GSM services.The Department of Telecom (DoT) yesterday granted three companies - Reliance Communications, HFCL and Shyam Telelink - the right to use GSM technology in their existing licence areas where they currently offer mobile services using CDMA technology. The move makes Reliance Communications, which runs GSM services in seven circles (the North-East, Assam, Orissa, West Bengal, Madhya Pradesh and Bihar), ready to offer GSM services in other circles.Cellular Operators Association of India (COAI) today said it will challenge the government's decision to allow CDMA players to offer GSM services.