A polling method using orthogonal signalling for Wireless Local Area Networks

The point coordination function (PCF) of the IEEE 802.11 WLAN facilitates deterministic frame transfer by a polling mechanism. This enables to support quality of service. Despite this benefit the PCF could be inefficient at low-to-medium traffic loads because it always polls all stations regardless of their actual demand. To overcome this drawback, we introduce a novel polling scheme where all stations simultaneously report their status by sending orthogonal signals, and a BS identifies and polls only those stations having data to send. The feasibility of orthogonal signalling is evaluated in a realistic channel model where multipath fading and additive white Gaussian noise are applied. Moreover, channel utilization of the proposed scheme is investigated analytically, and compared with other schemes through simulation. The evaluation results show that the proposed scheme considerably outperforms other schemes at low-to-medium traffic loads.