  For greedy block sparse recovery where the sparsity level is unknown, we
derive a stopping condition to stop the iteration process. Focused on the block
orthogonal matching pursuit (BOMP) algorithm, we model the energy of residual
signals at each iteration from a probabilistic perspective. At the iteration
when the last supporting block is detected, the resulting energy of residual
signals is supposed to suffer an obvious decrease. Based on this, we stop the
iteration process when the energy of residual signals is below a given
threshold. Compared with other approaches, our derived condition works well for
the BOMP recovery. What is more, we promote our approach to the interference
cancellation based BOMP (ICBOMP) recovery in paper [1]. Simulation results show
that our derived condition can save many unnecessary iterations and at the same
time guarantees a favorable recovery accuracy, both for the BOMP and ICBOMP
recoveries.
