(Telecompaper) Brazilian operators Vivo, TIM, Claro and Algar Telecom have registered to take part in the 4G auction, scheduled for 30 September, while Oi and Nextel have dropped out of the race. On offer will be six lots of 2x10 MHz in the 700 MHz band, of which three will have national coverage. The fourth lot does not cover the concession areas of regional operator Sercomtel (Londrina in Parana) and the municipalities in the states of Sao Paulo, Goias and Minas Gerais served by Algar Telecom. The fifth and sixth lots are regional and are equivalent to the areas of Sercomtel and Algar, respectively. A second bidding round is foreseen if there is no winner for a lot in the first round. The Brazilian government hopes to receive at least BRL 7.7 billion from the auction of the 700 MHz frequency band, but without Oi's participation this goal might not be achieved. Oi, which is faced with serious financial problems, said it plans to use the 2.5 GHz band to offer 4G to its customers and meet coverage obligations by 2017, with the possibility of also using the 1.8 GHz frequency band in the future. Nextel said it will continue monitoring investment opportunities for growth and development of the business, adding it could be interested in the auction of leftover frequencies that Anatel could organize next year.