Fig. 6
From: Optimized sleep strategy based on clustering in dense heterogeneous networks
Outage probability of the system. The outage probability will be zero if there is no sleep mechanism in the system as shown in Fig. 6. It is possible that some small BSs enter the sleeping mode when the system takes the sleep strategy. It is shown that the outage probability increases firstly because the UEs’ growth rate is larger than the activation rate. And the outage probability will gradually decline as the increasing number of activated small BSs. Therefore, the outage probability firstly increases and then decreases with the user’s number. In the proposed strategy, we take the sleep mechanism in each cluster to improve the efficiency of sleep and activation. Hence, we can see the decline of outage probability in the system as a whole