Friendly coexistence of voice and data traffic in IEEE 802.11 WLANs

The combination of VoIP and WLAN technologies has created a new attractive service, wireless VoIP, and its interest has been increasingly growing in a variety of environments such as offices and public areas. However, mixing voice with data traffic introduces QoS issues because 802.11 DCF does not provide any QoS mechanism. In this paper, an enhanced version of the legacy DCF is proposed in order to support friendly coexistence of voice and data. Every downlink transmission of data packets in an AP, voice packets pending in its queue are simultaneously sent together. It can be easily implemented with packet bursting technique. Thus, voice traffic is hardly interfered by dynamic data load, and its QoS can be consistently protected within an acceptable level. Additionally, the proposed MAC scheme is fully backward compatible with DCF, and requires only partial modifications of the AP MAC protocol. The simulation results show that the proposed scheme achieves a high level of voice QoS with data load dynamics. In other words, our solution enables voice and data traffic to coexist harmoniously, greatly reducing interference of data with voice.