The development of wireless sensor networks (WSN) can be motivated by several types of applications. However, these applications demand an energy-efficient WSN that can prolong the network lifetime and can provide high throughput, low latency and delay. Designing wireless sensor networks with the capability of prolonging network lifetime catch the attention of many researchers in wireless system and network field. Contrasts with Mobile Ad Hoc Network system, Wireless Sensor Networks designs focused more on survivability of each node in the network instead of maximizing data throughput or minimizing end-to-end delay. In this paper, we will study part of data link layer in Open Systems Interconnection (OSI) model, called medium access control (MAC) layer. Since the MAC development of energy aware MAC Protocol for wireless sensor layer controls the physical radio part, it has a large impact on the overall energy consumption and the lifetime of a node. This paper proposes a analytical approach that tries to reduce idle energy consumption, and shows the increasement of network end-to-end arrival rate due to efficiency in energy consumption from time slot management.