%0 Conference Paper %B IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC) %D 2009 %T Wideband Spectrum Sensing in Cognitive Radio: Joint Estimation of Noise Variance and Multiple Signal Levels %A R. López-Valcarce %A Gonzalo Vázquez-Vilar %B IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC) %C Perugia, Italy %8 June 21-24 %G eng