Providing QoS for Symmetrical Voice/Video Traffic in Wireless Networks

Voice over IP (VoIP) and voice-video over IP (VIoIP) are becoming very popular and widespread. These types of real-time services produce streams that are almost symmetrical in nature. A new token passing media access control (MAC) developed by our group, called wireless token network (WTN), has been designed with QoS guarantees in mind. We have previously shown in our previous paper (2006) that WTN supports a higher number of VoIP clients compared to 802.11e due to its higher channel efficiency. In this paper we show that WTN also provides superior QoS for bidirectional streams such as VIoIP due to a higher proportion of channel access given to the access point (AP). Performance results are generated by benchmarking WTN against IEEE 802.11 DCF, IEEE 802.11e EDCA and SpectraLink SVP MAC protocols. These results show that whilst appropriate for unidirectional traffic, these current popular solutions do not provide QoS for streams in both directions, due to design constraints which treat the access point as a single client node.