Efficient Power Management Scheme Considering Inter-User QoS in Wireless LAN

In wireless LAN, power saving is the essential issue to the node since the node has the limited battery. Hence, the nodes can use the Power Saving (PS) mode unless transmitting or receiving packet exists for the certain period. For the PS node to receive the buffered packet in Access Point (AP), the PS nodes periodically check the Traffic Indication Map (TIM) field in the beacon frame that contains the information about buffered packet. If the buffered packet exists, they must transmit the PS. POLL to the AP. The AP transmits the buffered packet to the node that succeeds to transmit the PS_POLL. However, when the node transmits the PS-POLL, the transmission order is determined without any priority. Therefore, we propose the efficient power management scheme to support inter-user QoS and reduce the power consumption in wireless LAN. In the proposed scheme, the node with high priority transmits PS_ POLL earlier than that with low priority, so the node with high priority receives the buffered packet faster than that with low priority, and reduces the power consumption by converting the mode from Active Mode (AM) to Power Saving (PS) for remaining beacon interval (BI). Through the analysis and simulation, we show that the proposed scheme reduces power consumption and guarantees inter-user QoS compared to conventional scheme.