Adaptive traffic indication algorithm for energy efficiency in IEEE 802.16e systems

The efficiency of power saving mechanism on wireless communications will influence the time the mobile stations (MSs) can operate. Due to the characteristics of centralized control in WiMAX system, the sleeping period of each subscriber is dominated by a base station (BS) based on their service types, traffic loads, and expected sleeping periods. The power saving mechanism uses an exponential backoff sleeping window manner to determine the sleeping period of each MS. In recent researches, some of them optimize the sleeping period by estimating the packet inter-arrival time for improving the energy efficient. However, those mechanisms do not reflect the relationship between the traffic load and available bandwidth. That is, according to the available and priorities of connections, the lower priority connections can not receive data immediately and waste energy on the waiting time. Thus, in this paper, we propose an adaptive traffic indication algorithm (ATIA) to let MSS do the extend sleep on bandwidth unavailable condition, and illustrate an adaptively adjusting sleeping window scheme for delay versus energy consumption. Simulation results show that ATIA increase the degree of power saving with comparison to IEEE 802.16e; and further, it shows that ATIA is capable of combining with other power saving mechanisms and improve performance.