Proposal on wireless LAN MAC frame control in receive opportunity for flow QoS

(IEEE802.11 Wireless LAN) is becoming important since WLAN is widely deployed as an access network and also plays a key role in providing seamless QoS communication between wired networks and wireless terminals. Although much previous research has focused on increase of total throughput or available bandwidth in WLAN, very few have treated per flow QoS, i.e., individual TCP/UDP flow QoS. IEEE802.11e might provide prioritized QoS functions, but it has many limitations both in a number of classes and in effects on per flow QoS. Instead of 802.11e or other modifications of 802.11, we propose an approach both to providing per flow QoS and to keeping existing terminals from any modification or installation of additional software/hardware. The proposed idea is ROC (Receive Opportunity Control in MAC Frame), in which a MAC frame is completely delivered only if it has high enough priority; otherwise it is either discarded or an Acknowledge (ACK) is not sent. The frame that was discarded is forced to take back-off for retransmission, according to 802.11DCF. This results in QoS degradation for low-priority flows and eventually results in QoS improvement for high-priority flows. Performance evaluation shows that ROC causes some performance degradation in the total WLAN throughput but can not only achieve per flow QoS priority control but can also provide arbitrary throughput value