Comments on "Correlated Jamming on MIMO Gaussian Fading Channels

For original paper by Kashyap et al. see IEEE Trans. Inf. Theory, vol.50, no.9, p.2119-23, 2004 September. In the subject paper , a lemma concerning the convexity of a particular log-det function is proposed and proved. However, it is shown here that while the lemma itself is correct, the derivation of the proof is subject to a major defect. In this correspondence, the defect is discussed and amended, and a full and correct derivation using the same approach is also given