Jens P. Elsner Piotr Rykaczewski Christian Körner Friedrich Jondral Orthogonal Complex Hadamard Spreading Codes for I/Q Imbalance Mitigation in MC-CDMA Systems. 2661-2665 2007 conf/vtc/2007s VTC Spring http://dx.doi.org/10.1109/VETECS.2007.547 db/conf/vtc/vtc2007s.html#ElsnerRKJ07