@article {guillen06thechannels,
	title = {The sphere lower bound for rotated lattice constellations in fading channels},
	journal = {IEEE Transactions on Wireless Communications},
	volume = {7},
	year = {2008},
	issn = {825-830},
	author = {Guill{\'e}n i F{\`a}bregas, Albert and E. Viterbo}
}
