Enhanced channel scanning schemes for next generation WLAN system

The IEEE 802.11 standard based Wireless Local Area Networks (WLANs) are widely deployed and have gained greater popularity. It is anticipated that WLAN will play an important rule in the future wireless communication systems in order to provide several gigabits data rate. However, it has been a challenging problem to support the IEEE 802.11 WLAN devices to fully exploit the high throughput gains offered by the IEEE 802.11 standard whenever possible since the current channel scanning mechanisms in standard may result in unacceptable delay for network discovery. In this work, we review the behavior of passive and active channel scanning schemes of the current IEEE 802.11 specification, and also propose two enhancements for the active scanning mechanism based on the draft of IEEE 802.11ai standard. The proposed schemes can reduce the overhead of transmitted management messages while improving the channel scanning performance. In addition, it can also increase the speed of discovery of APs before associating with one and enable more precise discovery operations. Through simulation study, it is shown that simulation results can explicitly verify our expectations on the superorities of the proposed schemes.