A seamless handoff scheme with new AP module for wireless LANs support VoIP

Recently, wireless LANs based on the IEEE 802.11 standard have become popular and widely used, and voice over IP (VoIP) is one of the most promising to be used in mobile devices over wireless networks. Up to date, new technologies have improved providing high data rate to support various kind of real-time applications. However, besides the need for higher data rates, seamless handoff is another important issue to be addressed in order to continue supporting realtime services across wireless LANs. In this paper, we proposed a seamless handoff scheme that uses access point (AP) module with 2 transceivers in order to improve network efficiency in terms of supporting seamless handoff and balancing the traffic load in wireless network. In our proposed scheme, APs use the second transceiver to search for information of neighbor STAs in the transmission range, and later send the result back to associate AP, which in turn compare and analyze whether the STA should perform a handoff or not. The initial results from our simulations show the proposed handoff scheme is more effective than the conventional scheme in terms of low latency and traffic load is fairly balanced.