Wireless Sensor Networks (WSNs) have recently used in many applications like surveillance, military applications, etc. In such applications, the sensor nodes are expected to be work long period of time without recharging their batteries. To extend the network lifetime, some sleep scheduling techniques always used, which may cause communication delay in large scale WSNs. In this paper, although the existing system avoids delay there are still few challenges. So the proposed topology of a wireless network should be efficiently designed to achieve high network performance.