G. R. Jithamithra B. Sundar Rajan Minimizing the complexity of fast sphere decoding of STBCs. 1846-1850 2011 ISIT http://dx.doi.org/10.1109/ISIT.2011.6033869 conf/isit/2011 db/conf/isit/isit2011.html#JithamithraR11