Comments on "Optimal Utilization of a Cognitive Shared Channel with a   Rechargeable Primary Source Node"
  In a recent paper [1], the authors investigated the maximum stable throughput region of a network composed of a rechargeable primary user and a secondary user plugged to a reliable power supply. The authors studied the cases of an infinite and a finite energy queue at the primary transmitter. However, the results of the finite case are incorrect. We show that under the proposed energy queue model (a decoupled ${\rm M/D/1}$ queueing system with Bernoulli arrivals and the consumption of one energy packet per time slot), the energy queue capacity does not affect the stability region of the network. 
Ahmed El Shafie and Ahmed Sultan
cs.IT cs.NI math.IT