  Recent works have developed a simple and robust myopic sensing policy for
multi-channel opportunistic communication systems where a secondary user (SU)
can access one of N i.i.d. Markovian channels. The optimality of the myopic
sensing policy in maximizing the SU's cumulated reward is established under
certain conditions on channel parameters. This paper studies the generic case
where the SU can sense more than one channel each time. By characterizing the
myopic sensing policy in this context, we establish analytically its optimality
for certain system setting when the SU is allowed to sense two channels. In the
more generic case, we construct counterexamples to show that the myopic sensing
policy, despite its simple structure, is non-optimal.
