Investigation into packet delivery options for WLAN access points implementing unscheduled power save delivery

In this paper we propose and evaluate the performance of techniques for controlling the delivery of traffic to WLAN stations in power save mode. The options evaluated include using unscheduled automatic power save delivery for delay sensitive traffic while requiring stations to poll for traffic from delay tolerant applications, versus using unscheduled power save delivery for both types of traffic in cases where a station has multiple sessions running. Particular attention is paid to practical issues related to signaling when the power save buffers of an access point are temporarily empty, and the interplay of different delivery and implementation options supporting quality of service (QoS).